ITB Journal
Not a member yet
5999 research outputs found
Sort by
Influence of Centrality Indices of Urban Railway Stations: Social Network Analysis of Transit Ridership and Travel Distance
Get PDFThis empirical study calculated the network centralities of urban railway stations in Seoul using Social Network Analysis (SNA) and analyzed the effect of this value on the number of passengers and average travel distance at each station. Network centrality can be calculated using various methodologies. In this study, reach, betweenness, and closeness were used as network centrality indicators. A regression model was used with the characteristics of building use in the station catchment areas as control variables. This methodology was compared to previous studies’ methods for obtaining stations’ topology values. The adjusted R2 values increased by 0.272 and 0.220 for the respective models, explaining the number of passengers and the average travel distance, respectively; the number of significant variables also increased in both models. These results indicate that defining the network centrality obtained through SNA as the station’s topology could improve explanations of the number of passengers and the average travel distance by 27.2% and 22.0%, respectively, compared to previous studies. While this methodology is not new, this study demonstrated the advantages of using SNA to determine the centrality indices of urban railway stations
Qualitative Behavioral Analysis in Mosquito Dynamics Model with Wolbachia
Get PDFThe Aedes Aegypti mosquito is the primary vector that can transmit diseases to humans such as zika, dengue fever, chikungunya, and yellow fever. This mosquito species is controlled to reduce the frequency of its bites on humans. Several methods have been developed to control mosquito populations, ranging from natural insecticides to artificial ones. However, the impact of these insecticides leads to resistance. Wolbachia bacteria as a promising alternative in reducing the spread of viruses on humans due to free resistance. This work constructs a genetic population model in the form of differential equation system that describes mosquito population dynamics by involving random mating between mosquito populations with and without Wolbachia bacteria. The stability of the equilibrium was analyzed locally here. Numerical simulations and sensitivity analyzes are presented to confirm the analytical results and investigate the effect of the parameters involved on the model. The results show that the success of the expansion of Wolbachia-infected mosquitoes depends on the fitness level of the mosquito species. The more Wolbachia mosquitoes are released into nature, the more possibility this mosquito expansion will be successful
Model Populasi Pongo abelii dengan Perubahan Daya Dukung Lingkungan
No full textPongo abelii is an endangered orangutan species. The reduction of Pongo abelii can be caused by the removal or loss of orangutans from the population and habitat loss. In general, research on population dynamics with changing carrying capacity is rarely done and it is simulated in this study. We adopted the Verhulst logistic model to model the population dynamics of Pongo abelii. This study aimed to see the effect of increasing the carrying capacity on the population of the endangered Pongo abelii species. From the results of this study, it is concluded that for areas other than Tripa Swamp, Siranggas/Batu Ardan, and East Batang Toru (Sarulla), the addition of carrying capacity is one of the effective options that is urgently needed to maintain a large population of orangutans. For the Tripa Swamp, Siranggas/Batu Ardan, and East Batang Toru (Sarulla) areas, suppressing the number of orangutans loss population is needed to maintain the population, which consists of poaching as trade, conflict killing, hunting/food, wounding, and fire. The results of this study can provide suggestions for tackling the declining population of Pongo abelii species by prohibiting the expansion of the species’ habitatPongo abelii merupakan salah satu spesies orangutan yang langka. Pengurangan populasi dan daya dukung lingkungan mengancam kehidupan orangutan. Kami memodelkan jumlah populasi Pongo abelii dan daya dukung lingkungan orangutan yang berubah terhadap waktu pada berbagai area. Hasil penelitian ini menunjukkan bahwa penambahan daya dukung lingkungan sangat diperlukan untuk mempertahankan serta meningkatkan populasi Pongo abelii. Terkhusus daerah Tripa Swamp, Siranggas/Batu Ardan, dan East Batang Toru (Sarulla), diperlukan cara lain untuk mempertahankan jumlah populasi orangutan, yaitu dengan menekan angka pengurangan populasi
Perbedaan Model Teacher Centered Learning Dengan Student Centered Learning Terhadap Keterampilan Bermain Bulutangkis
Get PDFPenerapan model pembelajaran berdampak pada peningkatan keterampilan bermainbulutangkis siswa. Penelitian ini bertujuan untuk mengetahui perbedaan TeacherCentered Learning (TCL) dengan Student Centered Learning (SCL) terhadapketerampilan bermain bulutangkis. Metode dalam penelitian menggunakan eksperimendengan two group pretest-posttes design. Pengambilan sampel menggunakan tekniksampling jenuh, pada siswa yang mengikuti ekstrakulikuler bulutangkis sebanyak 40siswa (20 siswa kelompok TCL dan 20 siswa kelompok SCL). Instrumen menggunakanGames Performance Assesment Instrumen (GPAI) untuk mengukur keterampilanbermain bulutangkis. Analisis data menggunakan uji Shapiro-Wilk, Levene Statistics,Paired Sample t-Test dan Independent Sample t-Test dengan bantuan aplikasi SPSS 25.Berdasarkan pengolahan dan analisis data ditemukan terdapat pengaruh pada kelompokSCL (sig 0,000 < 0,05), tidak terdapat pengaruh pada kelompok TCL (sig 0,862 > 0,05),dan terdapat perbedaan pengaruh antara kelompok TCL dengan SCL sebesar (beda =1,39; sig 0,000 < 0,05). Jadi dapat disimpulkan bahwa terdapat pengaruh model StudentCentered Learning terhadap keterampilan bermain bulutangkis, tidak terdapat pengaruhmodel Teacher Centered Learning terhadap keterampilan bermain bulutangkis, danterdapat perbedaan pengaruh yang sugnifikans antara Teacher Centered Learningdengan Student Centered Learning terhadap keterampilan bermain bulutangkis siswaSMPN 1 Waled yang mengikuti ekstrakurikuler bulutangkis.Penerapan model pembelajaran berdampak pada peningkatan keterampilan bermain bulutangkis siswa. Penelitian ini bertujuan untuk mengetahui perbedaan Teacher Centered Learning dengan Student Centered Learning terhadap keterampilan bermain bulutangkis. Metode dalam penelitian menggunakan eksperimen dengan two group pretest-posttes design. Pengambilan sampel menggunakan teknik sampling jenuh, pada siswa yang mengikuti ekstrakulikuler bulutangkis sebanyak 40 siswa (20 siswa kelompok TCL dan 20 siswa kelompok SCL). Instrumen menggunakan Games Performance Assesment Instrumen (GPAI) untuk mengukur keterampilan bermain bulutangkis. Analisis data menggunakan uji Shapiro-Wilk, Levene Statistics, Paired Sample t-Test dan Independent Sample t-Test dengan bantuan aplikasi SPSS 25. Berdasarkan pengolahan dan analisis data ditemukan terdapat pengaruh pada kelompok SCL (sig 0,000 < 0,05), tidak terdapat pengaruh pada kelompok TCL (sig 0,862 > 0,05), dan terdapat perbedaan pengaruh antara kelompok TCL dengan SCL sebesar (beda = 1,39; sig 0,000 < 0,05). Jadi dapat disimpulkan bahwa terdapat pengaruh model Student Centered Learning terhadap keterampilan bermain bulutangkis, tidak terdapat pengaruh model Teacher Centered Learning terhadap keterampilan bermain bulutangkis, dan terdapat perbedaan pengaruh yang sugnifikans antara Teacher Centered Learning dengan Student Centered Learning terhadap keterampilan bermain bulutangkis siswa SMPN 1 Waled yang mengikuti ekstrakurikuler bulutangkis
A Discussion on Interdisciplinary Approach of Visual Art Syllabus in Malaysian Higher Education
Get PDFThis article contributes to the discussion on the need to adopt an interdisciplinary approach in the visual art syllabus, specifically in higher education in Malaysia. Over the last two decades, the academic world has faced rapidly advancing technology and the rise of Industrial Revolution 4.0 (IR4.0). Because of the increased level of high-tech software and hardware competency among students, universities are in dire need to improve and innovate their current syllabi. Hence, this study was carried out to discuss the need to adopt an interdisciplinary approach to improve current visual art syllabi in Malaysia. The topics that are explored in this paper include the definition of an interdisciplinary approach in visual art syllabi, the current status of visual art syllabi in Malaysia, factors that are important for the integration of art with other fields, and how an interdisciplinary approach can be implemented. The data used in this research were obtained from a seminar, in-depth interviews, and a literature review, and were analyzed using a qualitative method. The findings indicate that visual art education duly needs a new program or needs to be revamped into a future-ready curriculum. Therefore, an interdisciplinary approach, or the integration of two bodies of knowledge in one program, could be one of the solutions to this issue
Evaluation of Crash Energy Management of the First-Developed High-Speed Train in Indonesia
Get PDFCrash energy management is an essential evaluation stage of passive safety systems for high-speed trains. As a part of crash energy management, crash energy absorption has been researched for the last decade. The development of its components has also been performed individually. This paper presents a numerical analysis of the configuration of an energy absorption system for high-speed trains developed in Indonesia. Three placement configurations of the energy absorption system were investigated using explicit dynamic analysis in ANSYS. Total energy absorption, deceleration pulse, and deformation length were considered in the evaluation of the numerical analysis results. The collision criteria used in this study were according to EN 15227 and CFR 238 standards. This study revealed that the existing design could fulfill the energy absorption and average deceleration pulse required by EN 15227. Nevertheless, the existing design could not fulfill the energy absorption and maximum deceleration pulse required by CFR 238. It was also indicated that by positioning the anti-climber slightly forward, changing the deformation force of the crush box, and adding an impactor, the quality of energy absorption and average deceleration pulse could be improved
Forecasting of Engine Performance for Gasoline-Ethanol Blends using Machine Learning
Get PDFThe incorporation of alternative fuels in the automotive domain has brought a new paradigm to tackle the environmental and energy crises. Therefore, it is of interest to test and forecast engine performance with blended fuels. This paper presents an experimental study on gasoline-ethanol blends to test and forecast engine behavior due to changes in the fuel. This study employed a machine learning (ML) technique called TOPSIS to forecast the performance of a slightly higher blend fuelled engine based on experimental data obtained from the same engine running on 0% ethanol blend (E0) and E10 fuels under full load conditions. The engine performance predictions of this ML model were validated for 15% ethanol blend (E15) and further used to predict the engine performance of 20% ethanol blend fuel. The prediction R2 score for the ML model was found to be greater than 0.95 and the MAPE range was 1% to 5% for all observed engine performance attributes. Thus, this paper presents the potential of TOPSIS methodology-based ML predictions on blended fuel engine performance to shorten the testing efforts of blended fuel engines. This methodology may help to faster incorporate higher blended fuels in the automotive sector
Globalization and Diversification of Interior Decoration Styles and Their Impact on Pakistani Handicrafts
Get PDFWith the gradual advancement of globalization, cultural values and traditional decorative practices as well as people’s lifestyles have changed through digital awareness. This has seriously affected the interior decoration industry and brought challenges to the local handicraft industry. Pakistan’s traditional handicraft is famous in the world, but the flow of imported machine-made products in Pakistan has led to a decline of Pakistan’s handicraft industry. This research investigated which factors are involved in home decoration and to see if these factors are advantageous for the handicraft industry or not. The use of handicraft decoration objects varies among people when they design their houses. Thus, study conducted a survey, which found several factors that Pakistani people emphasize in relation to home decoration. Currently, these factors do not benefit the handicraft industry as people pursue a modern lifestyle and they consider handicraft objects without innovation and design outdated. Interior decoration is seen as a major aspect of traditional Pakistani life and culture, with distinct cultural characteristics. Inspired by the latest way of thinking, an interior design first exists as a concept and is then realized through careful planning. It is meant to evoke a specific mood through the strategic use of color, space, and style. In Pakistan, home accessories are generally and strongly influenced by the current fashion in the end market, with many changes brought about by consumers’ purchasing patterns, designers’ and decorators’ styles, and economic conditions. Keeping up with constantly changing trends is the main challenge faced by the traditional handicraft industry sector. In many cases, craftspeople are disconnected from the end market, which is a challenge for them to be able to profit from their work
Al-Cu Composite’s Springback in Micro Deep Drawing
Get PDFWith the recent technological trend of miniaturization in manufacturing industries, the rise of micro forming operations such as micro deep drawing (MDD) is inevitable. On the other hand, the need of more advanced materials is essential to accommodate various applications. However, a major problem are size effects that make micro scale operations challenging. One of the most important behaviors affected by size effects is the springback phenomenon, which is the tendency of a deformed material to go back to its original shape. Springback can affect dimensional accuracy, which is very important in micro products. Thus, this paper investigated the springback behavior of Al-Cu composite in MDD operations. Micro cups were fabricated from blank sheet specimens using an MDD apparatus with variation of annealing holding time. The springback values were measured and compared to each other. The results showed that different grain sizes lead to variation in the amount of springback. However, unlike in single-element materials, the amount of springback in Al-Cu composite is not only related to the thickness to grain size (t/d) ratio. Another factor, i.e., the existence of an interfacial region between layers, alters the mechanical behavior of the composite
A Comparative Study of Solid-State and Co-precipitation Methods for Synthesis of NMC622 Cathode Material from Spent Nickel Catalyst
Get PDFNickel, the main raw material for lithium-ion batteries (LIB), is currently the most in-demand metal. The rising need for nickel and current environmental concerns have underscored the importance of recycling waste metal to recover its value. Meanwhile, a significant secondary source with a high metal value is spent catalyst. In this context, the acid leaching method was used to recover nickel from spent catalyst. This study aimed to synthesize Lithium Nickel Manganese Cobalt Oxide 622 (NMC622) from spent catalyst. To determine the optimal method, a comparative analysis was conducted between solid-state and co-precipitation methods. Recycled spent nickel catalyst to be used for cathode material was examined by analytical methods, i.e., XRD, FTIR, SEM-EDX, and electrochemical performance testing. The XRD, FTIR, and SEM-EDX tests produced similar outcomes, consistent with previous reports. However, in the electrochemical test, the co-precipitation method showed a specific capacity two times higher than the solid-state method. The NMC622 from the co-precipitation method (NMC622-CP) yielded a specific discharge capacity of 132.82 mAh.g-1 at 0.1C, while the retention capacity was 70% for 50 cycles at 0.5C