bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication of Magnetic Ink Chromium Ferrite Using Iron Sand
Authors: Yulianto A , Rohman A
Published: June 2021

In this research iron sand was used as raw material for fabrication of magnetic ink of chromium ferrite. The first step of research was synthesizing iron sand into pigment of chromium ferrite using powder metallurgy method. The second step was processing pigment into magnetic ink. The ink was produced by mixture pigment into binder solution of polyvinyl alcohol and heated. While stirring the mixture was added alcohol as a solvent and additives of polyethylene glycol, propylene glycol, and glycerine by certain composition. The variation of pigment mass was 6 g, 8 g, 10 g, 12 g, 14 g, and 14 g. The produced ink was characterized its properties, those were structure using XRD method, colour, density, viscosity, organoleptic, CCD microscope, and magnetic susceptibility. Using XRD was found that the pigment have a structure of CrO.Fe2O3 with size of 84.81nm. The colour of ink was dark green. The brightness of the ink decreases with increasing pigment mass. The coordinates values of a* and b* was fluctuated. The ink viscosity was around 7.64 cP until 19.59 cP, the density was around 0.954 gr/cm3 until 1.007 gr/cm3. By organoleptic study was found that the ink can be used on the whiteboard. From CCD microscope was known that distribution of ink more evenly white increasing of pigment mass. The value of magnetic susceptibility was around of 1.500175×10−5 m3/kg until 1.504662×10−5 m3/kg.
Science literacy profile of student on landslide disaster mitigation in Semarang city
Authors: Astuti B , Suryaningsih I , Rusilowati A , Khumaedi  , Kusuma H H
Published: June 2021

The purpose of this study was to determine the profile of students’ science literacy on landslides disaster mitigation in Semarang City. This research method is a quantitative description with one shot case study. The sample of this research was the 10th grade students of SMA N 7 Semarang who were taken by using purposive random sampling technique. Data collection techniques used written tests, questionnaires and interviews. For data analysis using data triangulation technique in order to obtain qualitative descriptive data. The results showed that students’ ability to mitigate landslides from the aspects of scientific literacy which included aspects of knowledge, context, competence and attitudes was still low.
The effectiveness of hypercontent module to improve creative thinking skills of prospective physics teachers
Authors: Rufaida S , Nurfadilah N
Published: June 2021

Hypercontent module as one of Technological Pedagogical Content Knowledge (TPACK) learning device contains collaboration between technology, pedagogy, and material content equipped with Quick Response Code (QR Code) as a learning navigation tool that is open source for learning, so it is expected to improve students’ creative thinking skills in information processing as new knowledge through technological literacy. This study aims to analyze the effectiveness of the hypercontent module to improve creative thinking skills of prospective physics teachers. The hypercontent module contains various learning resources such as presentation, text, video, images, and exersice that can be accessed via QR Code reader. This research is a pre-experimental research with one group pretest postest design. The research subject is 16 students in Department of Physics Education Muhammadiyah University of Makassar. The data were collected through tests of creative thinking skills with indicators of thinking fluency, flexibility, elaboration, and originality. The results of data collection were analysed with descriptive analysis and N-gain test. This research shows that the hypercontent module is effective to improve the creative thinking skills of prospective physics teachers. This can be seen from the increase in the score of students’ creative thinking skills from 64.51 to 72.64 after implementing the hypercontent module.
Hamiltonian matrix representation of harmonic oscillator system with Linear-Cubic-Quartic (LCQ) perturbation
Authors: Aryani N P , Lalus H F , Wahyuni S , Ratnasari F D , Akhlis I
Published: June 2021

In this paper, we analyze the matrix representation of the energy operator (Hamiltonian) of the harmonic oscillator system when this system is perturbed by an LCQ perturbation. The LCQ perturbation is simultaneously acted on this system, so the total Hamiltonian is a summation of the pure oscillator harmonic operator term (in the annihilation and creation operator statement) and the three perturbation terms. In this work, we use three different small parameters for each term of the perturbation for keeping the generality. We use the simple algebraic method by using the Dirac notation and the well-known base vector of harmonic oscillator to analyze this problem. Next, we present every term of this operator in matrix representation and then adding them for finding matrix representation for the total Hamiltonian.
Transition probabilities of harmonic oscillator system with spatial Linear-Quadratic-Cubic (LQC) perturbation in time-dependent
Authors: Lalus Herry F. , Aryani N P
Published: June 2021

We analyze transition probabilities of harmonic oscillator system with spatial LQC (Linear-Quadratic-Cubic) perturbation in time-dependent. This system initially was in the ground state with no perturbation at t < 0, then at t ≥ 0, the system is perturbed by spacial LQC perturbation in time-dependent until t → ∞. We use the time-dependent perturbation theory to analyze this problem. In the initial state, before there is no perturbation, we define the ground state with the base ket of harmonic oscillator without perturbation. Next, when the perturbation is applied to the system, we compute the transition amplitude base on the system state presented above and then we get total wave function that depends on time. By getting this wave function, we can compute transition probability for the system. As a result, there are three transition probabilities, namely the transitions from the ground state to the first, second, and third excited state. There is no transition to others.
Exact meromorphic solutions of cubic Ostrovsky equation: Kudryashov method
Authors: Lalus Herry F. , Aryani N P
Published: June 2021

We analyze the cubic Ostrovsky equation which is a modification of Ostrovsky equation. This equation can be found in physical phenomena such as wave mechanism due to a rotating media. We use the Kudryashov method to solve this equation. Since this equation is one type of nonlinear partial differential equation, we initially transformed this equation into its nonlinear ordinary differential equation form. Next, we compute the Laurent series of this equation and we get two types of Laurent series with a second-order pole; the coefficients of these series are complex numbers so that the symmetrical form is complex conjugation. Based on these two Laurent series, we construct two types of solutions, each of which consists of elliptic solution (doubly periodic) in the form of Weierstrass-℘ functions, simply periodic solutions, and rational solution.
The effect of glass neutral density filter on illuminance measurement error
Authors: Nelfyenny  , Achmadi A , Prihhapso Y , Farhania W , Suryani D , Zaini H
Published: June 2021

We present an analysis of the illuminance measurement results when a glass neutral density filter (ND Filter) inserted between light source and photometer. ND filters are widely used as an alternative solution in illuminance calibration systems to perform lower illuminance level which caused by inadequate length of the photometric bench. However, there are some variables that must be considered when inserting ND filters in illuminance measurement, one of which is the perceived color temperature of the light source which is influenced by the non-flatness profile of the filter’s spectral. This research was conducted by calculating correction factor for each ND filters, which contribute to illuminance error. Six different ND filters in the range of 1% to 49% are used in this experiment. Scanning the spectral distribution of filter are done to analyzing the change of color temperature of the light source as it passes through an ND filter, due to the lamp must correspond to Illuminant A. This research shows the illuminance measurement error can be up to 20% proportionality to the transmittance as the effect of using ND filters. The results of this study are expected to provide recommendations for the calibration laboratory, especially in illuminance meter calibration.
Analyzing of the Indian Ocean Dipole (IOD) phenomena in relation to climate change in Indonesia: a review
Authors: Koesuma S , Andriani R D , Legowo B
Published: June 2021

IOD is another parameter that affects climate change, especially in tropical areas such as Indonesia. IOD is a global phenomenon that occurs due to differences in sea surface temperature anomalies in the western and eastern parts of the Indian Ocean. This paper aims to review several articles that discuss the Indian Ocean Dipole (IOD). The data used in this paper are the latest journals related to the IOD phenomenon in the last 10 years. From the results of the review, it is obtained a more detailed explanation of the influence of the Indian Ocean Dipole (IOD) in relation to climate change in Indonesia.
Senior high school student’s higher order thinking skills based on gender and grade
Authors: Faizah R , Taqwa M R A , Istiyono E , Ikhsanudin
Published: June 2021

The current curriculum in Indonesia focuses on developing higher order thinking skills. However, this achievement at the level of education varies widely, even in the same school. This study aims to determine the effect of differences in gender and grade of students on high school students’ high order thinking skills. This research was conducted by giving 45 points multiple-choice questions to 94 students in four class of XI senior high school. The items given are questions based on higher order thinking aspects. Based on the analysis results, 27 male students scored in the high domain, and only two male students scored in the low field. Twenty female students scored in the high field, and nine students achieved in the low field. The gander has a significant correlation to students’ higher order thinking skills, with an association coefficient or a contingency coefficient of 0.1. In other words, the student’s gender is affecting the student’s higher order thinking skills. The grade variable does not have a significant correlation with student’s higher order thinking skills. In other words, the student’s grade affects the student’s higher order thinking ability is not proven.
Optimization of bus frame with bending moment and torsion constraints using finite element method
Authors: Kurdi O , Haryanto I , Prahasto T , Widodo A , Satrijo D , Yob M S , Yulianti I , Nourie M H , Wijaya Y A
Published: June 2021

This paper presented the optimization of bus frame to obtain the optimum weight of bus frame. Failure of the frame can be caused by bending loads and torque experienced by the structure in the conditions of two wheel bumped and one wheel bumped. The optimization process applied is structural size optimization. The method used includes solver deck input and element criteria, input material used, making load collector and load step, running program, convergence test. Then a static linear analysis is performed using the finite element method to see the maximum stress that occurs in the frame, the magnitude of the Von-mises stress value is 1,303 × 103 MPa under static bending conditions and 1,305 × 103 MPa under static torsion conditions. The next step is size optimization which results in a mass reduction of 0.236 tons under static torsion conditions and 0.46 tons under static bending conditions.
The formulation of vector potential evolution equation on rapidly rotating and accreting neutron star in the frame of Zero Angular Momentum Observers (ZAMO)
Authors: Yasrina A , Andra D , Pramono N A
Published: June 2021

The equation for the dynamics of the magnetic field can explain the decrease in the magnetic field due to accretion. Maxwell’s relativistic equations formulate these equations. The formulation of the solution to the Maxwell equation is said to be correct if it is by the Schwarzschild space-time case by formulating the vector potential evolution equation. Maxwell’s second relativistic equation, the covariance tensor of the electromagnetic field, and the vector potential are used to obtain the equation for the evolution of the vector potential. All equations are calculated in the Zero Angular Momentum Observers (ZAMO) framework. The purpose of this research is to formulate the vector potential evolution equation for each component in a rapidly rotating and accreting neutron star. The results obtained have covariant terms with the slow rotating neutron star. However, the equation for a rapidly rotating neutron star has a more complex description. There are terms that cannot be simplified, such as in slowly rotating neutron stars.
Thermoelectric use in various renewable alternative energy source
Authors: Jumini S , Iswari R S , Marwoto P
Published: June 2021

Energy and environmental conservation problems are increasing every day. The use of electricity began to experience shortages by about 1.6 billion people. The use of fuel oil (BBM) in road transportation requires a larger number along with the number of means of transportation. On the other hand, there is an inefficient use of energy for some equipment used by humans. Gasoline and electric vehicles generally use inefficient internal combustion engines. About 25% of the combustion results are used for vehicle operations, and 40% is lost to waste heat that is wasted. Waste heat is also wasted on household appliances. Global warming and environmental pollution due to the use of inefficient energy are also increasing. Research by experts on thermoelectrics shows good results in overcoming inefficient use of energy and can provide solutions to energy problems and environmental conservation. Its use is flexible, because it does not require complicated mechanical structures, and is also environmentally friendly. This paper provides a review that reviews the use of thermoelectric in various equipment that produces waste heat energy that has not been utilized optimally.
Surface morphology of composite from mahogany leaves waste with citronella oil (Cymbopogon winterianus Jowitt) as a natural coating for antifungal of Pleurotus ostreatus
Authors: Masturi  , Alighiri D , Drastisianti A , Susilawati  , Fathurachman Y , Maesaroh S , Sunarno
Published: June 2021

In this work, citronella oil’s activity as a natural coating for antifungal on mahogany’s surface morphology(Swietenia mahagoni)leaves waste as composite was investigated. The composite material from mahogany leaves requires a coating that can inhibit fungi growth. Citronella oil was a natural material that can be used as an antifungal for coating this composite. The concentration of citronella oil used for the MIC (Minimum Inhibitory Concentration) assay was 0.1-2.0%. Based on the MIC of citronella oil can inhibit the growth of the fungusPleurotus ostreatusat the optimum concentration of 0.2% with inhibition of 33.33%. Coating of citronella oil on composites using several concentrations ranging from 0.0, 0.4, 0.8, 1.2, 1.6 and 2%, respectively. The surface morphology on composite with citronella oil as the natural coating was observed using a CCD camera microscope with a magnification of 50x showed that the growth of fungal spores on the composite surface began to be inhibited a concentration of 0.4%. This surface morphology of composite can prove that citronella oil can be used as an antifungal.
Colorimetric detection of metal ions using green-synthesized silver nanoparticles
Authors: Taufiq M , Eden W T , Sumarni W , Alauhdin M
Published: June 2021

Generally, the analysis of metal ions uses expensive and tedious techniques and involving complicated devices. Here, we developed a colorimetric-based detection of metal ions using green-synthesized of PVA-stabilised silver nanoparticles (AgNPs), which is simple and low cost. The linearity and sensitivity of AgNPs in detecting metal ions were determined from the absorbance and shifting of local surface plasmon resonance (LSPR) band in the visible range. The detection was carried out on Cu(II), Pb(II), Cd(II), Zn(II), and Mn(II). The most sensitive response was obtained on Cu(II) ions, among the five ions tested. The response showed a good linearity (R2= 0.9886) in the range of 0.2-1.4 ppm of Cu(II). Meanwhile, the sensitivity on Cu(II) resulted in the limit of detection and the limit of quantitation of 0.1609 mg.L−1and 0.5179 mg.L−1, respectively.
Cytotoxic effects of the synthesized Citrus aurantium peels extract nanoparticles against MDA-MB-231 breast cancer cells
Authors: Amalina N D , Wahyuni S , Harjito
Published: June 2021

Currently, nanoparticle is at fastest pace due to the enhanced implication in drug delivery system. The synthesis of chitosan nanoparticles through ionic gelation methods is becoming increasingly relevant due to the low cost involved and environment-friendly approach. In this study, cytotoxic effect of chitosan-Citrus aurantium peels extract nanoparticles (NPs-CA) against MDA-MB-231 breast cancer cells was investigated. The initial confirmations of NPs-CA were using Particles size analysis (PSA), which showed the size of NPs-CA. The Zeta potential was measured to check the stability of NPs-CA. The cytotoxic effect was carried out in MDA-MB-231 breast cancer cells under MTT assay. Based on PSA analysis, the size of F1 and F2 were ranging between 372 – 4472 nm and 94 – 373 nm, respectively. The zeta potential mean value of F2 NPs-CA 34,9 mV, it can be concluded that the particles show less chances for agglomeration. On the various test concentration, the F2 NPs-CA performed better cytotoxic effects than Citrus aurantium peels extract with IC50 value of 83 μg/mL and 320 μg/mL, respectively. These findings pose a positive impact to expand further studies in the development of nanoparticle to cancer therapy.
Isotherm adsorption of free fatty acid in waste cooking oil used activated carbon of banana peel as bio-adsorbent
Authors: Rengga W D P , Seubsai A , Roddecha S , Yudistira A , Wiharto A D
Published: June 2021

The reduction of free fatty acids from the remaining cooking oil was successfully adsorbed by activated carbon from the banana peel biomass. The difference in activation temperature in making activated carbon causes it to adsorb free fatty acids, different from frying frozen fries in palm oil. The method used is adsorption with a batch system. The adsorbent used was biocarbon from banana peels, activated at 600, 650, and 700°C for 1 hour. Powdered activated carbon products were used in the adsorption process with a pass size of 200 mesh. Isotherm modeling with 1% activated carbon content in used cooking oil was carried out to determine the equilibrium constant in the Temkin, Langmuir, Freundlich, and Dubinin Radushkevich models. The suitability for adsorption of free fatty acids, which tends to approximate the Freundlich model. Adsorption of free fatty acids with activated carbon at 700°C effectively follows the Freundlich Isotherm Adsorption Model (R2 = 0.97) with physical adsorption energy, and the maximum capacity is 27.404 mg/g as seen from other isotherm models.
Esterification of α-pinene using TCA/Zeolite Y catalyst
Authors: Wijayati N , Isnaini F N , Kusumastuti E , Rakainsa S K , Mahatmanti F W , Lusiana R A
Published: June 2021

Indonesian turpentine oil contains α-pinene (70-90%), β-pinene (5-10%), and 3-carene (4-10%). This study aims to determine the effect of temperature, time, and mass of the catalyst on the α-pinene esterification. The esterification was carried out at 25, 40 and 50°C for 1, 2, 3, and 4 hours with variations in the catalyst mass of 100, 300 and 500 mg. This reaction was carried out in a three neck round bottom flask equipped with a heater, thermometer and magnetic stirrer. The ester produced in the α-pinene transformation through the esterification is carvyl acetate. The optimum results were obtained at temperature of 40°C and the addition of catalyst of 500 mg with α-pinene conversion of 67.81% and selectivity of carvyl acetate at 81.92% for 1 h.
Microwave irradiation assisted methoxylation of α-pinene using potassium alum [KAl(SO4)2] catalyst
Authors: Wijayati N , Mahatmanti F W , Rakainsa S K , Herlinawati M D , Lusiana R A
Published: June 2021

Methoxylation is a reaction to produce of ether compounds using methoxy ions. The α-pinene methoxylation using potassium alum catalyst was carried out using a microwave with power variations of 320, 480 and 640 W, mass of the catalyst 0.3; 0.6 and 0; 9 g, and mole ratio of reactants 1:15, 1:30 and 1:45 mole. Identification of the reaction results was performed using GC, GC-MS and FT-IR. The product obtained in α-pinene methoxylation is mirtenyl methyl ether (MME) and terpinyl methyl ether (TME). The conversion of α-pinene with the variation of 480 W microwave power, mass of catalyst 0.3 g and mole ratio of reactants 1:15 at 120 seconds was 99.82% with the selectivity of MME and TME were obtained 32.0 % and 1.4%, respectively.
The synthesis results comparison of spirooxindole derivatives using TiO2 and TiO2/SiO2 catalyst
Authors: Amanda M H , Cahyana A H , Abdullah I
Published: June 2021

Derivatives of Spirooxindole compounds with the peculiarities of a heterocylic ring-shaped framework, therefore these compounds have biological activities that play an important role in the pharmaceutical field. The synthesis of spirooxindole derivates was successfully carried out with the Multicomponent reaction that plays a role in it is the Knovenagel condensation reaction and followed by Michael’s addition reaction. The derivative reaction of spirooxindole compounds is more effective and efficient in synthesis time because the reaction uses a heterogeneous catalyst of TiO2/SiO2 nanoparticles. In this research we will compare using TiO2 and nano TiO2/SiO2 as catalyst. This study produced a spirooxindole compound derivative using precursors such as, isatin, malononitrile and 1,3-diketone groups varied with baribituric acid. The results of the reaction optimization obtained that reaction time of 60 minutes, at temperature of 50 ° C, and a catalyst load of 12.5%. The yield percentage obtained under optimum conditions was found 82,72% in TiO2 catalyst and then 86, 81% in TiO2/SiO2 catalyst. The yield was obtained after the compound was recrystallized using hot ethanol. The characterization of TiO2 and TiO2/SiO2 catalysts was confirmed using FT-IR, XRD, and SEM-EDX. While the characterization of the spirooxindole compound derivate products was confirmed by TLC, FT-IR, and UV-Vis.
Study on the quality of irrigation water in the talawaan irrigation channel using the Sodium Adsorption Ratio (SAR) Method
Authors: Wantasen S , Luntungan J N , Tarore A E , Lumingkewas A , Ogie T B
Published: June 2021

The suitability of water for irrigation purpose can be determined using the Sodium Adsorption Ratio (SAR) method. The method describes the extent of sodium will be absorbed into the soil. This study aims to assess the water quality of the Talawaan river as a source of irrigation water using the Sodium Adsorption Ratio (SAR) method. The measurement was carried out by field observation at the tertiary channel and laboratory analysis of water samples obtained from the channel. The concentration of Na+, Ca2+, Mg2+ were calculating using the SAR. Sampling of Water quality parameters was determined using the Composite Sampling, then analyzed with the UV-Spectrophometry The data referring to the standard values from Ayers and westcott. The results showed that the Sodium Adsorption Ratio (SAR) at the Talawaan irrigation varied from 1.33 meq/l to 1.55 meq/l. These results meets the requirements of the Ayers and Westcott standard standard, which stated that SAR at less than 3 meq/L is good quality standard (table 2). SAR value affects soil conditions, especially related to soil structure and soil permeability and infiltration.
Vapor-solid mixer design for cinnamal tea production
Authors: Cahyono E , Kurniawan C , Anggraito U
Published: June 2021

The utilization of natural products that potentially act as anti-cancer has been widely investigated. Our previous study in 2019 on microencapsulation of several essential oils, including citral with aldehyde moiety and citronellal from lemongrass, and cinnamaldehyde from cinnamon, has proved remarkably successful to prevent cancer risk (chemo-prevention). The study is then extended to produce tea-based products with citral and cinnamaldehyde oil additives as cancer risk prevention drink drinks. The study will aim to optimizing the mixer parameters to overcome the volatility rate of essential oil. The research was designed with the Analysis, Defining, Development, Implementation and Evaluation (ADDIE) model. It was conducted to make sure that all the machine parameters work efficiently. The developed machine is equipped with a heater tank and mixer. The heater tank and mixer capacities are 2.2 L and 4.0 L, respectively. The maximum pressure tank is up to 4.0 bar, and the recommended pressure works are 2.0 bar. The heating temperature maximum is 170 °C, and it will also keep the essential oil stability. The vapor-solid mixed gently at 20 rpm to produce a well-mixed product. Power consumption up to 1500 watts at 220 V (50 Hz). However, the product at the mixing time of 60 seconds with the gas flow 2 bar was perfectly obtained.
Secondary metabolite learning model from Taxus sumatrana with ethnoscience integrated inquiry using online system and google form application
Authors: Sudarmin  , Mursiti S , Sarwi S , Listiaji P
Published: June 2021

During the current Covid-19 pandemic, learning was carried out using an online system, so many training activities, seminars, and lectures were carried out online. In this research, a secondary metabolite learning model fromTaxus sumatranawill be applied with Ethnoscience Integrated Inquiry. Learning activities are carried out online via video conference. Furthermore, to evaluate the learning process and results, the google form application is used. This research is institutional research from an Ethno-STEM based Learning Center. Lessons are conducted online for two hours and during the webinar activity. Learning consists of presenting material, question-answer, and the evaluating of the training process and results using the google form application. The learning activities were attended by 128 participants from 69 universities, 14 schools, and 4 non-educational institutions. The evaluation results of the evaluation show that the implementation of the secondary metabolite learning model fromTaxus sumatranais very satisfying, engaging, creates curiosity, and motivates to understand STEM literacy and local culture. Besides, an evaluation of the material mastery shows a moderate average score of 12.53 from a maximum score of 20.00.
Automatic geotagging using GPS EXIF metadata of smartphone digital photos in tree planting location mapping
Authors: Prasetiyo B , Alamsyah  , Muslim M A , Subhan  , Baroroh N
Published: June 2021

Tree planting is one of the programs that are currently being promoted. The location of tree planting is important to be monitored in the future. Tree planting activities carried out on the UNNES campus always carry out online documentation and reporting. However, the problem is the difficulty in obtaining the coordinates of the location of the plants because what is currently done is clicking on maps manually. In this research, we designed automated geotagging tree planting photos. Digital photos from smartphones are read, then extracted EXIF information to get GPS coordinates. Then the coordinates are obtained automatically, then stored in the database. The coordinates can be reversed to display on maps. In our experiment, we study in two cases. Case 1 the original photo near the building, Case 2 the photo near the forest. We can show that the result of mapping represents the actual state of the photo. So, the use of GPS information on photo smartphones can be an alternative solution in terms of documenting planting photos to get an accurate location.
Evaluation performance recall and F2 score of credit card fraud detection unbalanced dataset using SMOTE oversampling technique
Authors: Prasetiyo B , Alamsyah  , Muslim M A , Baroroh N
Published: June 2021

Unbalanced data becomes an interesting research and continues to be studied because of its uniqueness. Unbalanced data requires special treatment prior to making the data balance. In this paper, our study to investigate the performance of unbalanced dataset using diverse oversampling proportion. We use SMOTE to gerentae new syntethic data, then we classify using random forest algorithm. In our experiment we generate new sampling with start 20%, 40%, 60%, 80%, and 100% of majority class, so that the data balancing until 50%: 50%. Each new generated data, we train the data using classification technique. Then, evaluate each algorithm performance. We show that the highest F2 score i.e: 85.34 and 84.93. The new data generated is 60% of majority class, result F2 score 85.34, then the new data generated from 100% of majority class result F2 score 84.93.
Web-based expert system to determine digital forensics tool using rule-based reasoning approach
Authors: Ramadhani E , Pratama H R , Wahyuni E G
Published: June 2021

Digital forensics is a method to trace the digital evidence using knowledge of science. There are several stages in the method of digital forensics. Each stage has their own way to use the method collaborate with the tool of digital forensics. Nowadays, there are tools that we can use in digital forensics. Therefore, not all the tool coming with the help document on how to use the tool. This situation makes the investigator have to check the feature of the tool one by one in order to suit which one is the best tool to use in some stage. To overcome this problem, we made a system to determine the right tool in digital forensics using rule-based reasoning approach. The result of this paper is web-based system to determine the right tool in digital forensics. The system shows that only 40% in suitability to help the investigator to determine the right tool. This cause by lacking of the rule consists in the reasoning approach.
Autocorrelation analysis of COVID-19 based on hijri calendar
Authors: Darmawan G , Rosadi D , Ruchjana BN , Hermansah
Published: June 2021

Indonesia is a country with a majority of Muslims. The Covid-19 outbreak to Indonesia concerns moments during Islamic holidays. There are many Islamic holidays from March to July, such as Ramadhan, Shawwal, and Eid al-Adha. This study aimed to investigate the relationship between after and before Covid-19 case (lag 1). This study also discussed the relationship among three cases per month for both calendars (Islamic and Gregorian calendar). Auto conversion data from daily to monthly of Hijri and Gregorian was compared by determining the autocorrelation on three cases (confirmed, recovered, and death cases) in both calendars. The auto-correlation test using the Islamic month had 0.747 confirmed cases, 0.711 recovered cases, and 0.461 death reported cases. In the meantime, auto-correlation test using Gregorian month had 0.013 confirmed cases, 0.085 recovered cases, and -0.203 death cases. We also calculated the monthly autocorrelation of Covid19 cases from March to August 2020; the result showed that autocorrelation values were high for both calendars. However, the value of autocorrelation from March to August, Gregorian calendar is higher than Hijri calendar.
Inventory control and distribution of medicine stocks by using a just in time method based on interactive web applications
Authors: Efrilianda D A , Umam K , Aulia A F
Published: June 2021

Management of an inventory data within an agency requires an interactive management system to provide ease and informative data presentation. Data processing using an interactive system makes it easy for users to understand and interact with data, especially if the agency concerned is an agency that is in charge of long-term data storage, complex data processing, data collection and data distribution processes, controlling inventory availability, and data collection conducted every day. Data storage and conventional data processing has several weaknesses such as high error rate in data processing, the system is not interactive so that it troubles and impedes the inventory data collection process by users, and can produce data ambiguity that can cause misinformation. By using the inventory control model Just-In-Time (JIT) Inventory method that allows the compilation of data collection and inventory stock requests as needed so that it can easily distribute and minimize wasted stock, the processing, storage, and data collection of a particular data inventory can be controlled well and can provide clearer information. As a result, implementing inventory control methods into a web application can provide web applications that have better functionality in processing, storing, and collecting data.
User requirement and prototype design of radio streaming using mind map model for “Forum Diskusi Radio Ponorogo” association
Authors: Asy’ari N A S , Muriyatmoko D
Published: June 2021

Forum Diskusi Radio Ponorogo (FDRP) is an association with consist of four radio station. Namely is Duta Nusantara FM, Suara Gontor FM, Romansa FM, and Songgolangit FM. Nowadays, FDRP as a terrestrial radio has some problem, and the first problem is to broadcast signal because the area is limited covered. The second problem is the listener are turning from traditional broadcasting to smartphone radio streaming, either using mobile apps or a website. To sustain this radio industry, they must switch to streaming radio via internet. This research aims to explore the need for building the radio streaming to expand the reach of radio broadcast and to design radio streaming media as a collaborative convergence movement. This study uses a mind map model by conducting observations, interviews and discussions to identify initial user needs and prototype techniques to determine the needs of streaming radio applications. This research produces a list of collaboration needs in maintaining the existence of the radio industry in Ponorogo and a prototype design of streaming media for a collaborative radio. For further research, it is hoped can be continued at the stage of making media and implementing streaming radio.
GIS-based spatial autocorrelation analysis and use of aerial photos metrics for land price per plot: a case study of Tembalang sub-district
Authors: Subiyanto S , Amarrohman F J , Giardi NDU
Published: June 2021

Tembalang sub-district is included in the suburban area of Semarang which is growing very rapidly in the housing market growth sector. Research on housing policies and existing land market value mechanisms was carried out by empirical analysis using traditional econometric models with multiple regression analysis and GIS-based spatial autocorrelation models. This research was conducted by modeling land prices based on land parcels from the interpolation of land price samples from the field survey results as well as analyzing the level of data closeness to the Tax Object Selling Value (NJOP). Land parcel data was created using the 2018 metric aerial photograph (10 cm spatial resolution). The dependent variable in the regression analysis model used data on the average value of land prices for each zone in 2018. The variables used in the first modeling, namely the geographic location, transportation accessibility, trade center and service intensity were used as independent variables. The apply Radial Basis Function (RBF), spatial autocorrelation model, in integration and comparative analysis of models with a focus on the analysis of factors affecting land prices, especially heterogeneity of spatial characters.
Design and development of a web GIS for management and performance evaluation of agricultural farms of sahar food industries company (SFIC)
Authors: Oliazadeh S , Khoram M R , Abbasi M
Published: June 2021

The web has changed everything, and GIS is no exception. Web GIS, as a combination of web and Geospatial information system or science (GIS) has become an evolving discipline. Web GIS provides all GIS functions, including easy access to spatial information, display, storage, editing, management, manipulation, analysis, and sharing of spatial information anywhere in the world at a relatively low cost and easily for end users. Has accepted. In this article, we will discuss the key technology of digital spatial information management system (Web GIS) of digital farms, then we will introduce SFIC. Finally, we design and develop a Web GIS as a management system with the aim of providing a suitable platform for the realization of visual management performance and also evaluating the performance of agricultural farms. This management and monitoring system helps decision makers and professionals to easily make appropriate decisions to increase crop production, management, updating spatial and descriptive farm information, and other related activities. Sahar Web GIS Agricultural Farm Management Spatial Information System helps ordinary and non-expert users to easily access information and improves the necessary measures for making decisions in this field.
Low-cost educational robotics for promoting STEM education
Authors: Abidin Z , Arifudin R , Hardyanto W , Akhlis I , Umer R , Kurniawan N
Published: June 2021

Robotics in education has been gaining attention from teachers and researchers in education. The use of robotics in education allows teachers to combine four disciplines, namely science, technology, engineering, and mathematics (STEM), to promote student learning simultaneously. With educational robotics, teachers can make science and mathematics concepts more concrete in a real-world context by combining technology and engineering altogether. This paper explores the designing process of educational robotics to promote STEM learning. Teachers were involved in designing and constructing robots. The “Big Ideas” exploration became an essential step to gather any insights from teachers on how robotics are built.
Development of postgraduate school’s digital library as a repository of digital collections
Authors: Abidin Z , Zulaikha I , Wicaksono D W , Umam K , Aulia A F
Published: June 2021

The development of information and communication technology offers advantages for library management. The ease of access to the internet makes it easy for us to access the library’s digital collection without any time and space limitations. Currently, many digital libraries have been developed in various universities to complement the existence of conventional libraries. This digital library’s presence can be a solution for traditional libraries to overcome existing limitations and constraints. This current study discusses how Universitas Negeri Semarang’s postgraduate school digital library is developed. The waterfall method and was used to guide systems development. This paper outlines how the digital library is used to give a portrait to the users of some features offered.
Knowledge management system in a higher education institution: Development of an expertise search system
Authors: Sugianto  , Abidin Z , Putra A T , Budiman K
Published: June 2021

Knowledge management constitutes determining factors for organisational effectiveness, organisational performance, and sustainable competitive advantage in higher education institutions (HEIs). HEIs create new knowledge through research works and community services, distribute knowledge through teaching and learning, and transfer knowledge through consultancies and scientific discussions. A knowledge management system (KMS) is considered essential for HEIs to facilitate knowledge management. This paper outlines the KMS development process of the Faculty of Mathematics and Natural Sciences of Universitas Negeri Semarang as a platform for advancing the faculty as an organisation. Data collections were conducted through forum discussions to gather information and identify current issues related to data used in KMS development. Some information technology experts, faculties, and top management staff were actively involved in the discussions. The obtained data were analysed and then applied in the system, namely the expertise database and conference database. The iterative model was employed as a guideline for the development of KMS. This model enables the developer to revisit the system once it needs to be updated in the future.
Analysis of TB epidemic model with relapse and treatment
Authors: Sutimin  , Herdiana R , Utomo R H S , Permatasari A H
Published: June 2021

Tuberculosis (TB) is an infectious disease becoming a serious health problem that causes mortality and morbidity. A model of Tuberculosis spread by incorporating the effect of relapse and susceptible from recovery individuals, as well as treatment is studied. The existence of endemic equilibrium is shown through the basic reproduction ratio. The analysis results show that the non endemic equilibrium is global stable if the ratio value is less than unity, the endemic equilibrium the global stable if the ratio value is greater than unity. The results of study show that the relapse factor affects in the decrease of healthy individuals, and treatment of chemoprophylaxis is more significant in preventing the spread of TB disease compared to therapy.
Forecasting retail sales based on cheng fuzzy time series and particle swarm optimization clustering algorithm
Authors: Ariyanto R , Tjahjana R H , Udjiani T
Published: June 2021

Use of the conventional forecasting method, which is based on trend data with average sales in the last few months, results inaccurate forecasting due to a large difference in data, this is the same as fuzzy forecasting with the same interval length or static. Therefore, this paper recommends using the Cheng forecasting method combined with the Particle Swarm Optimization (PSO) algorithm. We use an artificial intelligence, i.e., PSO algorithm to set non-static length of intervals each cluster on Cheng method. The comparison of this method yields a better root mean square error (RMSE) value for each cluster on the recommended method.
The total irregularity strength of caterpillars with odd number of internal vertices of degree three
Authors: Maulana M R , Rosyida I , Mulyono
Published: June 2021

Given a graph G consisting of vertex set V and edget set E, repectively. Assume G is simple, connected, and the edges do not have direction. A function λ that maps V ∪ E into a set of κ-integers is named a totally irregular total k-labelling if no vertices have the same weight and also the edges of G get distinct weights. We call the minimum number k for which G has totally irregular total k-labelling as total irregularity strength of G, ts(G). In this article, we construct labels of vertices and edges of caterpillar graphs which have q internal vertices of degree 3 where q is 5,7, and 9. We obtain the exact values of ts in the following: n + 2 if the caterpillars have q=5 internal vertices, n + 3 for q=7, and n + 4 for q=9.
Improving absorption of students with special needs by the use of Mathematical Multi-purpose Videos
Authors: Sugiman  , Suyitno A , Pujiastuti E
Published: June 2021

This article begins with a research collaboration between the Director of Seameo-Sen, based in Melaka Malaysia, and the Study Center in the Field of Learning for Students with Disabilities of FMIPA UNNES. The research objective to obtain the results of the analysis that revealed the use of the Multi-purpose Videos of Mathematical Teaching Aids to increase the absorption of students with special needs. The research method is with a qualitative approach. The subjects of this study taken one Malaysian Special School teacher, a Partner Researcher from Seameo-Sen, and the four of visually impaired and the mental retardation students at State Special School (SLBN) in Salatiga. Data analysis: data reduction, data presentation, data interpretation, and drawing conclusions, accompanied by class visit activities at SLBN Salatiga by applying Multi-purpose Videos of Mathematical Teaching Aids, interviews, Focus Group Discussion (FGD), and triangulation of data sources. As a result, by applying the Multi-purpose Videos of Mathematical Teaching Aids there was an increase in the absorption of SLB students. In conclusion, SLB needs to use Multi-purpose Videos of Mathematical Teaching Aids to increase the absorption of students with Special Needs in Mathematics.
Reverse optimization and capital asset pricing model in the application of the Black Litterman portfolio
Authors: Subekti R , Abdurakhman  , Rosadi D
Published: June 2021

In the application of the Black Litterman model on portfolio construction, the terms of reverse optimization and Capital Asset Pricing Model (CAPM) are often associated with the Black Litterman process. This study explains the Black Litterman model from two perspectives: reverse optimization and the CAPM formula. Two portfolios are built with different starting points and without any lambda difference as a risk aversion coefficient, a scalar tau, and views return in the Black Litterman strategy. Both models are applied in the Indonesian stock market, and the empirical comparison of both portfolios are demonstrated. The result shows that both approaches can build a portfolio using the Black Litterman with a similar weight allocation.
Reception of mathematics education and mathematics exercises program to increase intelligence quotient
Authors: Aurachman R
Published: June 2021

Intelligence Quotient (IQ) and scholastic intelligence are believed to be of fixed value for each individual. Although some research has emerged in the field of neurology which states otherwise. IQ is an important factor that helps a person get a job and improve his career. Through this paper, a proposed program to increase IQ using mathematics education and mathematics exercises will be presented. It is hoped that in the future this program can be tested and implemented for many people in need. The research show that majority of student are interested to program which designed to increase IQ.
Optimization of Naïve Bayes uses the genetic algorithm for classification data
Authors: Salim A , Alfian M R , Andriani H , Afifah N
Published: June 2021

Classification is one of the statistical methods to classify data systematically. However, if there is a large amount of data and various features, it often results in low accuracy. For this reason, methods are needed that can handle the data with various types. One method that can handle this problem is Naïve Bayes. Naïve Bayes is one of the methods used for classification data. This method requires a stage of selection of independent variables in increasing the accuracy of the model from Naïve Bayes. So we need an excellent method to fix these deficiencies uses a Genetic Algorithm (GA). Genetic algorithm is one of the metaheuristic methods used in optimization techniques. The data used are septic tank data in East Surabaya with eleven independent for classification data. The result of classification accuracy using Naïve Bayes is 72.7%. When Naive Bayes was used with a genetic algorithm, the classification accuracy was increased is 90.9%