KnE Life Sciences

Organoleptic Analysis of Egyptian Martabak with the Addition of Betung Bamboo Shoots (Dendrocalamus asper)

Laili Suhairi, Indani ., Abdullah ., Yuri Gagarin, Halimatussakdiah . — Wed, 27 Mar 2024 00:00:00 +0000

Betung bamboo shoots (Dencrocalamus asper) is a plant derived from the shoots of bamboo betung processed into additional stuffing in Egyptian martabak. Betung bamboo shoots contain 59 gm of phosphorus and 13 mg of calcium, so they are good sources of natural nutrients for the body. The purpose of the study was to determine the organoleptic characteristics of the Egyptian martabak from bamboo betung shoots and to determine consumer acceptance of the Egyptian martabak from bamboo betung shoots. This study used an experimental method with three treatments and 3 repetitions using a completely randomized design (CRD). Data collection techniques used observation tests conducted by 5 sources, and acceptance tests were carried out by 30 consumers. The results of the observation test were analyzed by calculating the average value obtained from the sources, while the acceptance test was analyzed using a one-way analysis of variance (ANAVA). The results of the observation by the interviewees chose the Egyptian martabak, bamboo shoots, treatment 3 with the code MM3 with the addition of 70 gm of bamboo shoots, the average value was 23.31. The results of the research acceptance test consumers like the color, texture, taste of the Egyptian martabak bamboo shoots betung treatment 1 (MM1) with the addition of 50 gm of bamboo shoots (25%), for the aroma consumers like Egyptian martabak bamboo betung shoots treatment 2 (MM2) with the addition of bamboo shoots bamboo betung 60 gm (30%). The resource person chose the Egyptian martabak, bamboo shoots, treatment 3 with the code MM3 in terms of color, aroma, texture, and taste. Consumers choose the Egyptian martabak bamboo shoots with treatment 1 (MM1) in terms of color, texture, and taste. Meanwhile, in terms of aroma, consumers chose the Egyptian martabak, bamboo shoots, and treatment 2 (MM2).

Keywords: organoleptic, Egyptian martabak, bamboo shoots.

Ring Artifact on SPECT Image due to Arbitrary Position of PMT Malfunction

Wed, 27 Mar 2024 00:00:00 +0000

To obtain high-quality images using SPECT (Single Photon Computed Emission Tomography) imaging, quality control (QC) is required. QC is periodically conducted on SPECT based on standard protocol. Ring artifact are one of the factors in determining optimal image quality. Uniformity is a parameter that determines the ring artifact on SPECT image, which can be appeared as full-ring or half-ring. Those artifacts were generated since one or more PMT (photomultiplier tubes) were malfunctioning. A copper sheet with size of 2 × 2 cm2 and 1 mm thick, attached to LEHR (Low Energy High Resolution) collimator in coordinates (x,y) depending on COR (Center of Rotation) of the gamma camera, was used to generate ring artifact during image acquisition using radioisotope 99

Detecting Quantum Topologic Phase Transitions Through The C-Function

Wed, 27 Mar 2024 00:00:00 +0000

Topological Quantum Field Theory or TQFT is a quantum field theory that calculates topological invariance in measurement theory and mathematical physics. In recent years, several attempts have been made to find efficient observations to determine the TQFT of quasiparticle properties. In this paper, we propose a different and very effective way to detect the critical points of TQFT by considering the system functions. We suggest the C-Function as a novel probe that is accurate for detecting the location of critical points on topological quantum. The C-function uses a holographic model to show a topological quantum phase transition between a simple topological isolation phase and a gapless Weyl semimetal. The quantum tipping point displays a strong Lifshitz-like anisotropy in the spatial direction, and a quantum phase transition that does not follow the standard Landau paradigm. The C-function precisely shows the global features of quantum criticality and distinguishes very accurately between two separate zero-temperature phases. Considering the C-function relationship with entanglement entropy can detect quantum phase transitions and can be applied outside the holographic framework.

Keywords: quantum topologic, phase transitions, c-function

Utilization of Solid Waste Pulp Green Liquor Dregs and Slaker Grits for Rooftile Production Application

Emrizal Mahidin Tamboesai — Wed, 27 Mar 2024 00:00:00 +0000

This study aims to utilize solid waste pulp green liquor dregs and slaker grits by analyzing the effect of adding solid waste green liquor dregs and slaker grits on water absorption and tile compressive strength, analyzing the chemical content of solid waste green liquor pulp dregs and slaker grits and concrete tile products and chemical morphology of the samples. The method used in this research is pressing. The results of the water absorption test for concrete roof tiles with the addition of 0%, 5%, 10%, and 15% solid waste green liquor pulp and slaker grits were 8.4%, 6.4%, 7.5%, and 9.4%. Testing the compressive strength of concrete tiles with the addition of 0%, 5%, 10%, and 15% solid waste green liquor pulp and slaker grits was 19.0 MPa, 19.7 MPa, 18.6 MPa, and 18.3 MPa. The chemical content of solid waste pulp before and after the finished concrete tile product is in accordance with the building blocks of the tile which consists of compounds Al2O3, SiO2, Fe2O3, and CaO. From the above test, it can be concluded that the addition of solid waste pulp can produce quality concrete roof tiles with reference to the value of SNI 0096-2007, that the maximum water absorption value of tile is 10% and the compressive strength of roof tiles is at least 6.0 MPa.

Keywords: solid waste, green liquor, slaker grits, rooftile

Electrical Properties of Gd- and Mn-Doped Fe2O3-LaFeO3- La2O3 Thick Films for Ethanol Gas Sensors

Wed, 27 Mar 2024 00:00:00 +0000

Herein, electrical properties of ethanol gas sensing based on Gd- and Mn- doped Fe2O3-LaFeO3-La2O3 thick films were investigated. The Gd- and Mn-doped Fe2O3- LaFeO3-La2O3 were synthesized by coprecipitation method and formed to thick films using screen-printing techniques with sintering temperature at 900 ∘C. X-ray diffraction and scanning electron microscopy were conducted to determine the crystal and morphological structures. The results showed that the synthesized materials have three phases i.e., tetragonal, cubic, and hexagonal, respectively for Fe2O3-LaFeO3-La2O3. Also, the average particle size is of about 0.51 μm. Among all those circumstances, synthesized materials indicate good performances as ethanol gas sensing that showed in the electrical properties’ measurement. It tested A differently in ethanol containing i.e., 0 ppm, 100 ppm, 200 ppm, and 300 ppm. The highest response to ethanol gases reached at 300 ppm, it is 332 with optimum temperature at 289∘C. We hope our findings could be beneficial and helpful in the perfect fabrication of ethanol gas sensors in future.

Keywords: electrical properties, thick films, doped, ethanol, sensors

Fabrication of Gadolinium Oxide-doped Fe2O3-LaFeO3-La2O3 Thick Films by Screen Printing Technique and Their Electrical Properties for Ethanol Gas Sensors

Wed, 27 Mar 2024 00:00:00 +0000

Recently, there have been many researchers who discussed screen printing techniques (SPT) as a good approach to fabricate the thick films for gas sensor applications. In this work, the SPTs were conducted to fabricate the thick films based on gadolinium oxide-doped Fe2O3-LaFeO3-La2O3 that were applied as ethanol gas sensors. The crystal and morphological structures were investigated using x-ray diffraction and scanning electron microscopy, respectively. It shows that there are three phases of the crystal structure of gadolinium oxide-doped Fe2O3-LaFeO3-La2O3 i.e., rhombohedral, orthorhombic, and hexagonal. The morphological structure shows an average particle size of about 0.61 μm. Furthermore, the electrical properties measurements were explored to ensure the performance of thick films in detecting the ethanol gases. Th measurements were conducted in the range of temperature of about 310 ∘C to 325 ∘C and in the various ethanol gas containing, it is 0 ppm, 100 ppm, 200 ppm, and 300 ppm. This result showed that the highest response of thick films in the existence of ethanol gases (300 ppm) is 427 with an optimum temperature of 319 ∘C. It is also confirmed that SPT has an excellent approach in thick film fabrication to produce gas sensor devices with good performance.

Keywords: fabrication, gadolinium oxide, doped, thick films, screen printing, electrical properties, ethanol, sensors

Modification of Pickle Goatskin with Silver Nanoparticles Using Brown Algae (Padina sp.) With Assisted Microwave

Wed, 27 Mar 2024 00:00:00 +0000

The objectives of this study were to determine the effects of modification of goat skin with silver nanoparticles prepared using brown algae (Padina sp.) and assisted microwave on hydrophobic properties, antimicrobial activity, mechanical properties, and biodegradability of goat skin. The synthesis of silver nanoparticles was carried out using the microwave method with a bioreductor of brown algae extract (Padina sp.) and a stabilizer of a starch solution. Characterization of the resulting silver nanoparticles was conducted by determining the wavelength utilizing the UV-Vis instrument and the particle size with a particle size analyzer (PSA). Characterization of the modified goat skin was conducted by measuring hydrophobicity through the sessile drop method, the antimicrobial activity test on modified goat skin was done by determining the clear zone against Escherichia coli (gram-negative bacteria) and Staphylococcus epidermidis (gram-positive bacteria). The mechanical properties of modified goat skin were analyzed by measuring the tensile strength of the skin. The characterization with UV-Vis on the resulting silver nanoparticles revealed 426 nm in maximum absorption and the diameter of silver nanoparticles by using PSA was 58.2 nm. Based on atomic absorption spectroscopy (AAS), the study showed that as many as 99.25% of silver nanoparticle has coated the surface of pickle goat skin. The modification of goatskin by adding silver nanoparticle can increase antibacterial activity of goatskin. The contact angle and the tensile strength of goatskin after modification were 81.49o and 14.63 MPa. The clear zone of goatskin after modification against Staphylococcus epidermidis and Escherichia coli were 9.33 mm and 8.87 mm, respectively. Meanwhile, the best biodegradability was the unmodified goatskin. Thus, modification by nanoparticles can decrease the biodegradability of goatskin.

Keywords: pickle goatskin, silver nanoparticles, brown algae

Generalization of Goursat's Theorem for Subrings of Direct Products of n Rings

Muhsang Sudadama Lieko Liedokto, Hery Susanto, I Made Sulandra — Wed, 27 Mar 2024 00:00:00 +0000

Bauer et al. describe Goursat’s theorem, representing the characteristics of subgroups of a direct product of two or more groups. In this paper, we expand into a ring structure that describes the characteristics of subrings of a direct product of rings. This research method is to analogize the evidence by Bauer et al. in the group for generalization. In our main results, every subring of the direct product of rings is determined by ring epimorphism between the ring and factor ring.

Keywords: Goursat’s theorem, subrings, rings

The Effect of Yeast Antagonist Isolated from the Fermentation of Cocoa Beans (Theobroma cacao) from Lampung, Indonesia, on the Growth of Aspergillus flavus UNJCC F-55

Wed, 27 Mar 2024 00:00:00 +0000

Mold is one of the microorganisms that causes damage to cocoa fruit because it produces mycotoxins as secondary metabolites that can decrease the crop yield. One type of pathogenic mold that destroys cocoa fruit is Aspergillus flavus. A. flavus produces aflatoxin B1 which is the most potent hepatotoxin and carcinogen to humans. Amongst the most effective ways to avoid alpha-toxin contamination in cocoa beans is to inhibit the growth of A. flavus in the beans. However, the use of pesticides and fungicides can increase the development of resistant strains of fungi and have a negative impact on the environment and human health. Therefore, we need other alternatives such as bio-control agents using antagonistic microorganisms, including yeasts. Thus, this study aims to characterize yeasts isolated from the fermented cocoa beans (Theobroma cacao) from Lampung, Indonesia, and evaluate their ability to inhibit the growth of Aspergillus flavus UNJCCF-55. The methods used were yeast screening, dual culture technique for antagonistic test, and morphological characterization. The 37ºC-growth screening gave 89 out of 98 yeast isolates. The subsequent antagonist test resulted in 13 isolates with the highest inhibition zone against A. flavus UNJCCF-55. These yeast isolates were macroscopically of smooth surface, butyrous texture, milky white color, irregular edges, and convex elevation. Microscopic observation showed that the isolates have oval cell shape, asexual reproduction of budding, and non-hyphae structure.

Keywords: yeast antagonist, cocoa fermentation, aspergillus flavus

Antagonistic Activity of Cellulase-Producing Yeasts Isolated from Cocoa Fermentation Against Pathogenic Molds Collected from Damaged Cocoa Fruits

Wed, 27 Mar 2024 00:00:00 +0000

The presence of pathogenic molds in post-harvested cocoa beans poses a significant problem to most Indonesian farmers. Pathogenic molds secrete phytopathogenic toxins which cause rotting, seriously damaging the cocoa fruits. The common pathogenic molds found in damaged cocoa beans are Phytophthora palmivora and Phytophthora megakarya. These molds are so far controlled by using chemical pesticides, whose long-term use is potentially harmful to human health and the environment. Thus, a healthier and safer alternative is needed, especially using biological agents such as yeasts. Some yeasts produce cellulose-degrading enzymes that can possibly break down the fungal cell wall which is composed mostly of the polysaccharide’s chitin and glucan. In this study, yeasts were isolated during the cocoa fermentation process, followed by screening for cellulolytic activity using direct planting and paste method, and subsequent antagonistic testing by double culture technique. Out of 128 yeast isolates, 77 possessed cellulase activity, with 6 of them having the highest activity index. Antagonistic activity test of these 6 isolates (C1.0.4, C1.1.3, C2.3.10, C2.3.14, C3.5.11, and C3.3.1) against the pathogenic molds resulted in isolate C3.3.1 showing the highest inhibition percentage from the 2

Isolation of Dark Septate Endophyte (DSE) from Ferns (Pteris Vittata) Roots

Wed, 27 Mar 2024 00:00:00 +0000

Dark Septate Endophytes (DSE) are a group of ascomycetes that live in intracellular and extracellular root tissue to facilitate plant growth and stress tolerance in extreme environments. However, little is known about the DSE fungi isolated from certain plant roots such as Pteris vittata, especially under drought condition. Pteris vittata is known for its ability to live in various types of substrates and ecosystems. In this study, we obtained DSE fungi from the fern roots Pteris vittata collected from the area of Universitas Negeri Jakarta. DSE isolation was carried out by inoculating the Pteris vittata fern roots with a size of 0.5 cm on the surface of sterilized PDA media for 5-7 days at 27∘C. Observations were made every 24 hours using a stereo microscope to see the first hyphae appeared from the plant roots. The results exhibited 13 samples of roots with hyphae colonization and were suspected to be DSE fungi. Of the 13 root isolates, only 3 isolate (PP2, PP4A, and PPB) showed the DSE growth (23%) with melanin pigment. The morphological characteristics of endophytic DSE fungi collected from Pteris vittata roots represented septate hyphae, brownish to black colony color, a growing zone, and a velvety texture. For the isolate PP2, it showed sclerotia while for the isolate PP4, it exhibited light brown colonies.

Keywords: isolation, DSE, ferns, pteris vittata, roots

Potential of Coral Resilience Post Bleaching in 2016 in the Water of Ujong Seuke East Coast of Weh Island Indonesia

Wed, 27 Mar 2024 00:00:00 +0000

Mass bleaching occurred in 2010 in Southeast Asia waters such as Thailand, Malaysia, and Indonesia. One of the Indonesian waters that experienced bleaching was Weh Island area, which then underwent bleaching again in 2016 and had impacts on the coral ecosystem. Substrate changes and coral cover conditions are noteworthy to determine the potential for coral recovery after bleaching. Therefore, the study aims to measure the condition of coral cover and the potential for coral resilience after bleaching in 2016. Benthic data collection used the Point Intercept Transect method while measuring coral resilience potential used the resilience index through coral cover indicators, fleshy seaweed, and rubble. The observation showed that the coral cover in the waters of Ujong Seuke was 34%, fleshy seaweed by 2.83%, and rubble by 21.17%. This research concludes that the condition of coral reef ecosystems after the bleaching phenomenon in 2016 was in moderate condition, and it has a high potential for resilience.

Keywords: coral, bleaching, water, ujong seuke, east coast, Weh Island

Analysis of Macroalgae Diversity in the West Coastal of Pananjung Beach, Pangandaran

Wed, 27 Mar 2024 00:00:00 +0000

The needed information about the diversity data in the area that can be used in ecological areas in the future is requested to be investigated. This study aims to analyze the diversity of macroalgae on the west coast of Pananjung beach, Pangandaran nature reserve. The study was conducted from March to April 2020. This research used a survey method using three stations representing the research region. Sampling was taken out in the intertidal zone of the Coastal Coast of West Pananjung, Pangandaran nature reserve, West Java using the purposive sampling method. Data taken consisted of macroalgae types found at each observation station and measurements of environmental data consisting of pH, temperature, salinity, and flow velocity. The results showed that there were 21 species of macroalgae grouped into 9 orders, 13 families, and 3 divisions. The research can conclude that macroalgae in Pananjung Barat Beach Pangandaran have an index value that indicates a moderate category, an evenness index classified as a low category, and a dominance index classified as a low category that shows the dominant species was there and it was Padina australis.

Keywords: macroalgae diversity, west coastal, Pananjung beach.

Monitoring the Diversity of Lizards and Snakes (Reptilia: Squamata), Along the Boyong-Code River Area, Province of Daerah Istimewa Yogyakarta

Wed, 27 Mar 2024 00:00:00 +0000

A reptile is a group of animal consists of testudines, crocodiles, lizards, and snakes. Most reptiles are capable of occupying wide range of habitats with different environmental conditions. One of the preferred habitats for reptiles is a river. Boyong-Code River is one of the rivers that flow across the Province of Daerah Istimewa Yogyakarta (DIY). Research on the diversity of lizards and snakes in the Boyong-Code River has been done in 2012. This research aims to acquire new data on the diversity of herpetofauna in the Boyong-Code River and compare it with 2012 data research. The comparison purpose is to monitor the species diversity dynamics after 5 years. The data of herpetofauna diversity were acquired using a combination of several methods, i.e., VES (Visual Encounter Survey), riverbank cruising, and transect. Sampling areas in 2012 and 2017 were divided into three locations, i.e., upstream, midstream, and downstream. Species diversity of lizards and snakes in the Boyong-Code River in 2017 consists of eight species of lizards (lacertilians: squamates: reptiles) and four species of snakes (serpents: squamates: reptiles). Species diversity dynamics were equal for lizards in 2012 and 2017; meanwhile, there were more species of snakes in 2012 compared to 2017.

Keywords: monitoring, diversity, lizards, snakes, reptiles, squamates, boyong-code river, Daerah Istimewa Yogyakarta

Phytochemical Profile and Sensory Evaluation of Natural Vinegar from Mixed Fruits and Flowers of Melastoma malabathricum L. with Variations of Starter Concentration and Fermentation Time

Safrida Safrida, Maim Matualiah, Fitrah Asma Ulhusna, Gholib . — Wed, 27 Mar 2024 00:00:00 +0000

Melastoma malabathricum L. is a wild plant in Aceh that can be used as a traditional medicine. This research aimes to determine the phytochemical profile and sensory evaluation of the fruit and flower vinegar of Melastoma malabathricum L. This research used a completely randomized design (CRD) consisting of two main groups, Saccharomyces cerevisae 5 days and 10 days with six treatments. Both the groups were added with Acetobacter aceti concentrations of 5%, 10%, and 15% which were fermented for 28 days. This study conducted phytochemical screening, total phenol and flavonoid test, and sensory evaluation. The results showed that the phytochemical test of the vinegar contained flavonoids, saponins, tannins, polyphenols, and terpenoids. The results of the sensory evaluation or organoleptic test showed that there was no significant difference in the color, acceptability, and Aroma of vinegar in all treatments but there was a significant difference in the taste of vinegar (p<0.05). The preferred vinegar was in the P5 treatment with a neutral taste. This natural vinegar product can be used as a beneficial beverage for public health.

Keywords: phytochemical, sensory evaluation, vinegar, Melastoma malabathricum L, mixed fruits and flowers, starter concentration, fermentation time

Structure and Dominance of Macrozoobenthos as Biomonitoring Instrument in the Reuleng River, Leupung, Aceh Besar, Indonesia

Wed, 27 Mar 2024 00:00:00 +0000

The Reuleng River is a mangrove area located in Aceh Besar district. Environmental changes that occur in the structure and composition of the mangrove ecosystem in the Reuleng River affect the macrozoobenthos conditions in the area. This study aims to determine the structure of the makrozoobenthos community as a biomomonitoring instrument in the mangrove ecosystem area. The study was conducted from February 2021 to May 2021. Determination of the sampling location was carried out using the purposive sampling technique and sampling was determined in three areas, namely upstream, middle stream, and downstream. The results showed that there were 19 species grouped into 4 genera and 12 families. The Macrozoobenthos Diversity Index in the Reuleng River area ranges from 2.62. The species that dominate the mangrove ecosystem area is the Faunus ater species with a dominant index value (0.16) and the lowest dominant species in the mangrove ecosystem is Thalassina anomala (0.01). No specific species were found that dominate the area. Based on descriptive observations, there is a group of Makrozoobenthos that has a relationship with the psychochemical quality of the air. The results show that the balance of the community in the area is still vulnerable and experiencing the impact of environmental pressures.

Keywords: Structure, dominant, macrozoobenthos, biomonitoring, reuleng river, Leupung

The Development of the Application of Centrifugal Force in the Geometric Design of Highways for Driving Comfort on the Pangalengan-Banjaran Roads

Wed, 27 Mar 2024 00:00:00 +0000

The Pangalengan-Banjaran road section has a winding geometric condition. The large number of bend geometries resulted in many accidents due to visibility, radius, and widening of the pavement at the corner, inappropriate road slopes caused many accidents to occur. The research method used in this research is the evaluative research method and quantitative method. The growth of suburban highway infrastructure in Indonesia has previously improved suddenly lengthways with economic growth. The geometrical strategy of the highway has previously remained planned by the typical requirements and needs of the purposes of the highway amenities constructed. The submission of physical science ideas in planning the geometrical stage as a meaning in smearing theoretic physical science to the identical-geometric design. A centrifugal strength in the physical science idea is a straightforward value in scheming geometric straight configurations of the road. Theoretical thoughtful of engineering term of scheming geometrical design viewpoint, has remained created on the method of centrifugal strength in the circumstance of effort on vehicles drive in the highway caisson disease. The operation has constantly remained built on variable quantity which remained strong-minded by thoughtful to spread on reason of rational usefully. These measures are lumped through dipping the result of bigger centrifugal strength. Furthermore, the submission is also able to decrease chance-disposed to areas due to the impact of size-centrifugal services on the geometrical plan of the highway.

Keywords: centrifugal force, geometric design, highways, driving comfort, Pangalengan-Banjaran roads

Input-Output Analysis on Pia Saronde Production Process Scheduling with Invariant Max-Plus Linear System

Wed, 27 Mar 2024 00:00:00 +0000

Max-plus algebra is one of the analysis methods of discrete event systems which has many applications on systems theory and graph theory. Max-plus algebra is a set of real numbers R combined with =-∞ equipped with operations max (⊕) and plus (⊗), can be denoted [(R]_ε,⊕,⊗) with [(R]_ε=R⋃{ε}) . The production process of pia saronde is one of the problems that can be analyzed using max-plus algebra. The production process of this product is sequentially carried out by making skin dough, filling, baking, cooling, and packaging the pia. The max-plus algebra theory was used in this research to determine the optimal time in the production scheduling of pia saronde. Meanwhile, the Invarian Max-plus Linear System (IMLS), max-plus algebraic theory, and the Discrete Event System (DES) were used to solve the production-related problems. IMLS analysis produces eigenvalues that represent the optimum production time. The results obtained the max-plus algebra model of x(k+1)=A^-⊗x(k), where A^-=A⊕B⊗C and y=K⊗x_0⊕H⊗u for input-output IMLS analysis. From the matrix A^-, eigenvalue λ= 226 and eigenvector v=[278 278 278 279 299 302 324 356 488] were obtained. Furthermore, the value of λ describes the pia production schedule at a time span of 226 minutes.

Keywords: input-output analysis, pia saronde, scheduling, max-plus linear system

Parameter Estimation and Hypothesis Testing on Bivariate Log-Normal Regression Models

Kadek Budinirmala, Purhadi ., Achmad Choiruddin — Wed, 27 Mar 2024 00:00:00 +0000

This study aims to introduce a bivariate Log-Normal regression model and to develop a technique for parameter estimation and hypothesis testing. We term the model Bivariate Log-Normal Regression (BLNR). The estimation procedure is conducted by the standard Maximum Likelihood Estimation (MLE) employing the Newton-Raphson method. To perform hypothesis testing, we adapt the Maximum Likelihood Ratio Test (MLRT) for simultaneous testing with test statistics which, for large n, follows Chi-Square distribution with degrees of freedom p. In addition, the partial testing is derived from a central limit theorem which results in a Z-test statistic.

Keywords: parameter estimation, hypothesis testing, bivariate log, normal regression

Parameter Estimation and Hypothesis Testing of Geographically and Temporally Weighted Bivariate Negative Binomial Regression

Christin Ningrum, Purhadi ., Sutikno . — Wed, 27 Mar 2024 00:00:00 +0000

When the response variable is discrete as a number (count) and there is a violation of the assumption of equidispersion, namely overdispersion or underdispersion then one of the appropriate alternative models used is Negative Binomial Regression (NBR). Moreover, if there are two correlated response variables and have an equidispersion violation, the Bivariate Negative Binomial Regression (BNBR) model is the solution. However, the BNBR model is considered inappropriate if the data contains spatial and temporal heterogeneity derived from panel data with the unit of observation in the form of a region. Therefore, a model is offered which is known as Geographically and Temporally Weighted Bivariate Negative Binomial Regression (GTWBNBR) which accommodates spatial and temporal effects. This study aims to conduct parameter estimates and test statistics for the GTWBNBR model. Estimated parameters use Maximum Likelihood Estimation (MLE) with BHHH numerical iteration because the MLE estimates are not closed-form. When the sample size is large, the Maximum Likelihood Ratio Test (MLRT) is used for simultaneous parameter testing while the test statistic for partial parameter testing approaches the Chi-Square distribution so that it can be tested using the Z-Test.

Keywords: parameter estimation, hypothesis testing, GTWBNBR

Traffic Generation in Surapati Gasibu Bandung City

Dadang Mohamad, Juang Akbardin, Muhammad Anelka Saiful Qashmal — Wed, 27 Mar 2024 00:00:00 +0000

Based on the data from the Bandung City Central Statistics Agency in 2020, population growth has been increased by 0.49%. The use of private vehicles, certainly affects the growth of traffic movements, especially at the Surapati Gasibu Intersection, Bandung City. To find out the traffic flow that passes through Surapati Street, a study was carried out using a movement generation model. The generation model uses the multiple regression analysis methods with the generated variable being the number of vehicles (Y) and the variables that influence it are the population (X1), the number of domestic tourists (X2), and the value of gross regional domestic income (X3) in Bandung. The data was obtained through the publication of the Bandung City BPS from 2012 to 2021 (10 years). Using the data analyst feature in Microsoft Excel, the regression equation is found to be Y = -7,003,565.898 + 3.213 X1 + 0.142 X2 and the growth value of traffic movement is at 2.39% per year. It means in 30 years the average traffic will grow by 20% and need a renewal intersection.

Keywords: traffic, generation, Surapati Gasibu, Bandung

COVID-19 Death Risk in Surabaya: Modeling by Spatial Point Process

Wed, 27 Mar 2024 00:00:00 +0000

The total death rate or Case Fatality Rate (CFR) due to COVID-19 in Surabaya is high, that is almost twice of the global CFR (1.4%). Utilization of high-resolution data has the potential to explore COVID-19 cases, not only recording cases at the district or city level but also at the patient’s domicile level so that they can provide more detailed spatial information. Meanwhile, research exploring the risk of death from COVID-19, especially in Surabaya using spatial point process model, has not yet been carried out. In this study, an analysis of the risk of death from COVID-19 in Surabaya will be carried out using the inhomogeneous Poisson point process model with covariates or external factors used including the density of the COVID-19 referral hospital location and the proportion of confirmed COVID-19 population aged > 60 years per districts. Our model shows that referral hospitals (exp( ) = 1.03295) and places of worship (exp( ) = 1.03835) have a significant effect on death risk from COVID-19. So, there is a need for special handling for areas that have a population with a vulnerable age (> 60 years) where at this age the human immune system will decrease.

Keywords: COVID-19, heath risk, spatial point process, surabaya

Forecasting the Export Unit Value Index in Indonesia Using the Single Input Transfer Function

Ika Fitria Millenia, Etik Zukhronah, Winita Sulandari — Wed, 27 Mar 2024 00:00:00 +0000

Export is one of the factors that increase the economic growth of a country. One measure of export activity that can describe economic growth in Indonesia is The Export Unit Value Index, which is an index that measures changes in the price of export commodities sold by residents of one country to residents of other countries. The purpose of this study is to predict the unit value index of exports in Indonesia using a single input transfer function model and to see the influence of the value of oil and gas and non-oil and gas exports on the unit value index of exports in Indonesia. The single input transfer function model is a model that describes the future forecast of a series (output series) obtained based on the past values of the output series and other time series (input series) that affect the output series. The results of this study obtained a transfer function model with the order (0,0,1) with a noise series following ARIMA (1,0,1). Based on this model, the export unit value index at time t is influenced by the unit value export index in the previous month and is influenced by the oil and gas and non-oil and gas export value in the same month. As indicated by its MAPE value of 4.89%, the forecast value does not diverge much from the actual value, which suggests that the transfer function model can be used to predict the export unit value index in Indonesia.

Keywords: forecasting, export unit value index, single input, transfer function

Implementing Time Series Cross Validation to Evaluate the Forecasting Model Performance

Wed, 27 Mar 2024 00:00:00 +0000

Theoretically, forecast error increases as the forecast horizon increases. This study aims to assess whether the statement is generally accepted or not. This study applies time series cross-validation to evaluate forecasting results up to seven steps ahead. As an illustration, we use Malaysia’s hourly electricity load data. Each hour is considered a series of each, so there are 24 daily series. Time series cross-validation with a 334 window was applied to 24 data series, and then each daily series was modeled with the Autoregressive Integrated Moving Average (ARIMA), Neural Network Autoregressive (NNAR), ExponenTial Smoothing (ETS), Singular Spectrum Analysis (SSA), and General Regression Neural Network (GRNN) models. In terms of mean absolute percentage error (MAPE) from one to seven steps ahead, we then evaluate the performance of all models. The experimental results show that the MAPEs obtained from the GRNN model tend to increase along with the theory. However, MAPEs obtained from ETS increase by up to three steps ahead and decrease after that. Among the five models, ARIMA, NNAR, and SSA produce a reasonably stable MAPE value for one to seven steps ahead. However, SSA has the most stable error value compared to ARIMA and NNAR.

Keywords: time series, cross-validation, evaluate, forecasting model performance

Parameter Estimation and Hypothesis Testing of Geographically and Temporally Weighted Bivariate Weibull Regression

Muhammad Eka Prasetya, Purhadi ., Sutikno . — Wed, 27 Mar 2024 00:00:00 +0000

In global regression, there is an assumption in the form of an error from a normally distributed model, so data that is normally distributed is required. But in reality, not all of the tested data meet the normal distribution. One of the theoretical distributions of continuous random variables that is often used is the Weibull distribution, where the Weibull distribution is a distribution that is often used to analyze the reliability of an object. If there are two response variables that are correlated with each other, the appropriate method used is Bivariate Weibull Regression (BWR). Spatial data has been widely used in various research fields. The Geographically Weighted Bivariate Weibull Regression (GWBWR) model is a model in which there are spatial effects, where there is spatial heterogeneity in bivariate regression with the response variable being Weibull distribution. In addition, panel data has also been applied in various cases, where panel data can provide information covering more than one time period. This can lead to a temporal effect. This study develops a model that can handle cases of spatial and temporal heterogeneity simultaneously, namely the Geographically and Temporally Weighted Bivariate Weibull Regression (GTWBWR) model. The parameter estimation in the model uses the Maximum Likelihood Estimation (MLE) method which gives results that are not closed-form, so it is continued with the Berndt-Hall-Hall-Hausman (BHHH) numerical iteration.

Keywords: parameter estimation, hypothesis testing, GWBWR

Implementation of Neural Network in Early Detection of Financial Crisis in Singapore

Fadia Mulyarti, Sugiyanto ., Sri Subanti, Etik Zukhronah, Winita Sulandari — Wed, 27 Mar 2024 00:00:00 +0000

The financial crisis that occurred in 1997 and 2008 had a negative impact on several countries, including Singapore. A financial crisis can occur suddenly so it can endanger a country’s economy if it is not prepared for it. Therefore, early detection of financial crises is needed as a form of crisis warning so that the government can anticipate and prepare appropriate policies. The independent variables used are monthly data of 11 key macroeconomic and financial indicators of Singapore’s economy from January 1990 to June 2021. The Perfect signal is used as the dependent variable in the crisis early detection system. This study aims to build a model of a financial crisis detection system in Singapore using Multilayer Perceptron Backpropagation (MLPBP) as a neural network algorithm by comparing the optimization of Stochastic Gradient Descent (SGD) and Nesterov-accelerated Adaptive Moment Estimation (Nadam). The optimal hyperparameter value in the model was searched using the grid search method based on the accuracy and obtained the best model with 11-11-1 network architecture, best optimization is Nadam, learning rate = 0.1; μ = 0.975; v =0.999; ϵ =[10]^(-8) ; batch size = 128, epoch = 100, and sigmoid activation function. Testing the model with data testing obtained an accuracy of 95.89%, a sensitivity of 98.36%, and a specificity of 83.33%. The results of the Perfect Signal prediction show that from January to June 2021 it is predicted that there will be no financial crisis in Singapore.

Keywords: neural network, early detection, financial, crisis, Singapore

Identification of Flowing Electrolyte Lead Acid Battery Operating Voltage

Wed, 27 Mar 2024 00:00:00 +0000

Identification of the operating voltage of a lead acid battery with 30% sulfuric acid electrolyte flow has been carried out. The battery consists of six cells with Pb and PbO as electrodes. The battery is equipped with a 1200 ml reservoir system to collect electrolyte and supply electrolyte to each cell. Each cell has electrolyte inlets and outlets at the top and bottom that circulate through each cell using a peristaltic pump. The battery prototype built was tested for five charge-discharge cycles with a constant current of 2 A for the charging process and 0.5 A for the discharging process using Turnigy Accucell. During the charge-discharge cycle test, monitoring and recording of voltage data is carried out using a Laptop PC. Data processing uses WebplotDigitizer and Microsoft Excel for data graphing. The results are analyzed and used to identify the operating voltage of the battery by taking the average voltage over five charge-discharge cycles. The average voltage is 13.98 V for the charging process and 12.11 V for the discharging process. Six-cell battery with full capacity works at a voltage range of 12.11-13.98 V. In the process of charging with a constant current of 2 A, the battery takes an average of 7.49 hours. So, the charging capacity can be estimated at 14,980 mAh. Whereas the battery discharge process takes an average of 11 hours with a constant current of 0.5 A to a voltage drop of 10.81 V. The resulting capacity of the discharged battery is 5500 mAh.

Keywords: flowing electrolyte, lead acid battery, operating voltage

Absorbance Optical Properties Calculation of ABX3 (A = Cs, Li; B = Pb; X = I, Br, Cl) Cubic Phase Using Density Functional Theory (DFT) Method

Aidha Ratna Fajarini Sidik, Pina Pitriana, Hasniah Aliah — Wed, 27 Mar 2024 00:00:00 +0000

Organic-inorganic perovskite is attracting much attention because it can be used for optoelectronic applications, such as solar cells and energy storage materials. In this study, we calculated the absorbance optical properties of perovskite ABX3 (A = Cs, Li; B = Pb; X = I, Br, Cl) in the cubic phase using DFT, one of the most common methods for analyzing the optical properties of materials. These studies were undertaken to determine the optical absorbance properties of the ABX3 perovskite as a potential for optoelectronic applications. The calculation was initiated by finding the optimization of pseudopotential and k_point, and pseudopotential GGA-PBE and k_point 8 x 8 x 8 are used as parameters to calculate absorbance optical properties. The absorbance calculation results are at a wavelength of 305.59 nm with a bandgap of 1.7608 eV for CsPbBr3, 380.78 nm with a bandgap of 2.27 eV for CsPbCl3, 301.86 nm with a bandgap of 1.35 eV for CsPbI3, 225.04 nm with a bandgap of 1.72 eV for LiPbBr3, 201.25 nm with a bandgap of 1.55 eV for LiPbCl3, and 211.58 nm with a bandgap of 1.24 eV for LiPbI3. These results indicate that ABX3 (A = Cs, Li; B = Pb; X = I, Br, Cl) has a good absorbance ability. These properties make ABX3 a potential material for optoelectronic applications.

Keywords: absorbance, optical properties, ABX3, cubic phase, DFT

Potential of Solar Energy Mapping in East Priangan Using Satellite Imagery and Environmental Based on GIS

Riki Purnama Putra, Seni Susanti, Indy Ramadhanti, Rena Denya Agustina — Wed, 27 Mar 2024 00:00:00 +0000

Renewable energy is an energy that can be used to turn on all the energy that is still widely used in the world, including in Indonesia. Solar energy is a renewable energy that uses solar energy as the main ingredient in the formation of electrical energy. Solar energy is one of the most likely energies in a country that is on the equator like Indonesia. One of the interesting problems is how to determine the most effective area for the installation of solar power plants to make the power received by the power plant more effective. This study aims to analyze the effective area for installing solar panels using a Geographic Information System (GIS) as well as mapping of Centralized Solar Power (CSP) and centralized solar photovoltaic (SPV) in the East Priangan area, West Java. The method used in this study is based on the use of remote sensing of the average annual horizontal irradiation (GHI) and Normal Direct Irradiation (DNI). Solar irradiation data (GHI and DNI) were obtained from data from the surface meteorological program and solar energy by NASA, while Land Use/Land Cover, and Digital Elevation Models were used with the use of GIS. The results show that high areas in East Priangan get more effective CSP and SPV results than low areas, but low areas show an average effectiveness value in denuded areas.

Keywords: solar energy, east Priangan, satellite imagery, environmental, GIS

Making Briquettes Variation Ingredient Durian Peel, Husk Rice, and Shell Coconut -- Impact on Strength, Burnability, Temperature, and Calorific Value

Indri Sari Utami, Dadi Rusdiana, Nahadi ., Irma Rahma Suwarma — Wed, 27 Mar 2024 00:00:00 +0000

The study aims to develop and test the characteristics of briquettes made from durian skin with a mixture of various compositions conducted that obtained briquettes from ingredients such as 100% durian peel, 100% husk rice, 100% shell coconut, 50% durian peel and 50 % shell coconut, 70% durian peel and 30% shell coconut, 50% durian peel and 50% husk, 70% durian peel and 30% husk, and 30% durian peel and 70% husk. Have been tested for variable endurance after dropping from a height of 180 cm as influenced by variation mixture that results in the test obtained the missing mass by consecutive 0.1 gr, 10 gr, 15.8 gr, 3.6 gr, 0.3 gr, 0.4 gr, 0.4 gr, 0.4 gr, 0.3 gr, and 0.4 gr. Test time burning by consecutive are 174 minutes, 120 minutes, 502 minutes, 410 minutes, 376 minutes, 406 minutes, 380 minutes, 367 minutes, and 280 minutes. The resulting calorific value consecutive are 105.8 kcal /kg, 124.9 kcal /kg, 135.3 kcal /kg, 38.2 kcal /kg, 121.5 kcal /kg, 59 kcal /kg, 95 kcal /kg, 128.4 kcal /kg, and 128.4 kcal /kg.

Keywords: briquettes, durian peel, husk rice, shell coconut

Community Perceptions on Conserving Watershed Areas

Wed, 27 Mar 2024 00:00:00 +0000

Conservation is one of the actions taken to maintain biodiversity and improve ecosystems. This study aimed to analyze the community’s view of conserving watersheds. The research method used is descriptive quantitative, involving the community as respondents to identify and analyze the proposed research instrument. Data were collected through a questionnaire, and community interaction data were collected through field observations and secondary data. The empirical data obtained was then analyzed and interpreted according to the research findings. The results of the research found that the community did not know much about conservation of biodiversity. Based on the community’s perception of conservation, it is necessary to emphasize to the community the importance of biodiversity as the basis for conservation to achieve disaster preparedness.

Keywords: conservation, biodiversity, ecosystem

Application of Generalized Reciprocal Method on 2D Seismic Refraction Data in Mt. Manglayang, West Java

Wed, 27 Mar 2024 00:00:00 +0000

The imaging of shallow subsurface structures, weathered rock thickness and velocity propagation distribution of the rocks can be identified by seismic refraction. This method is one of the geophysical exploration methods utilizing refracted wave once it reaches the boundary of subsurface layer. In this research we used the generalized reciprocal method (GRM) as one of the robust processing methods in analyzing subsurface data. This method was chosen due to its accuracy in interpreting shallow subsurface layer with highly undulating refractors by determining time velocity analysis, XY optimum distances, and time depth analysis, then, the expected depth values can be achieved. The acquisition of data for this research was conducted using 13 geophones with forward and reverse sources, the data were then picked to get travel time values and inverted to obtain real geological setting of the earth. The results were interpreted as 2 layers, the first layer had a velocity distribution of 499.289 m/s which was identified as a weathered layer with a thickness of about 4.74 meters, whereas the second layer was interpreted as clay rock with velocity distribution of 1270.433 m/s with the thickness reached up to 16 meters.

Keywords: generalized reciprocal method, 2D seismic refraction

Comparison Test Between Amrita Virtual Lab and Real Spectrometer on Refractive Index Using Blended Laboratory

Wed, 27 Mar 2024 00:00:00 +0000

Education in the 21st century is an era where learning is unconventional. Interactive learning in the 21st century can be done by conducting virtual or real laboratory activities, even by combining the two in one activity at once. Various innovations in virtual laboratories have spread to optical materials, especially refraction by using a virtual spectrometer. Conceptually, the refractive index is a measure of the bending ray of a light beam as it passes from one medium to another. The refractive index is given by measurement between the refractive index of air, the angle of the prism, and the angle of minimum deviation. The angle of the prism and the angle of minimum deviation can be measured with a spectrometer. The spectrometer is a scientific instrument used to separate and measure the spectral components of physical phenomena and can separate white light and measure individual narrow color bands. Other than an on-hand spectrometer, other tools that we can use to measure the angle of minimum deviation are by using a virtual spectrometer provided by several virtual labs. The study aimed to compare the result of refractive index between on on-hand spectrometer and a virtual lab. Here we report our study on spectrometer whether the virtual lab experiment yields the same results as the real lab. We compare both results of experimental data using data and graph analytics. The results of the study show that the difference in the index of refraction measured between the virtual lab and the real lab is about 0.2%. This shows that there is no significant difference between virtual lab and real lab.

Keywords: amrita virtual lab, real spectrometer, refractive index, blended laboratory

Effect of Moon Phase on Physical Parameters at the Mouth of the River

Winda Setya, Epa Paujiah, Yusri Amalia, Subagja Burhaanuddin — Wed, 27 Mar 2024 00:00:00 +0000

Light from the sun is the need for living things both on land and in the air. The moon, as a medium that reflects sunlight in one month, has several phases. This phase affects the situation on earth, especially river mouths. This study aims to determine the effect of the moon phase on physical parameters (water temperature and air temperature) at the mouth of the river. This research was conducted in 4 moon phases on the physics parameters at three coastal estuaries during the day and night. Based on the study results, it was found that the moon phase of the physical parameters is very influential on the number of micro-organisms. The number of organisms in each estuary also shows different characteristics according to moon phase conditions.

Keywords: moon phase, physical parameter

Energy Efficiency Comparison in Heating Water Using Gas, Electric, and Induction Cooktops and Determination of Container Emissivity Coefficient

Aas Wasri Hasanah, Adhitya Sumardi Sunarya, Sparisoma Viridi — Wed, 27 Mar 2024 00:00:00 +0000

A 1.315 kg stewpan is used to boil 1 kg water using three different type of cooktops, that is, gas, electric, and induction. The power of the electric cooktop is 600 W, a gas cooktop uses the maximum setting (large burner in control knob), and the induction cooktop has maximum power of 1200 W. We have observed two different settings of power: 600 W and 1200 W. In the first setting, we compared induction and electric cooktops, while in the second induction and gas cooktops were compared. We obtained energy efficiency about 67.24% and 56.2% for the first setting and 74.03% and 38.55% for the second, which shows that induction cooktop always gives better performance compared to the other cooktops. Besides this, we also investigated the energy leak from the stewpan to the environment through radiation, which should be the same, since all four observations were using the same container to heat the water.

Keywords: energy efficiency, heating water, induction cooktops, container emissivity coefficient