Sugiono Sugiono

Trains are one of the main forms of mass transportation that have proven to be a mainstay of public transportation in developed (England, Germany, the USA, Japan, etc.) and developing countries. Based on the results of an initial survey of 30 respondents who live near railway crossings in Indonesia, 70% reported disturbances, including hearing impairment, compared to residents farther from the crossings. This paper aims to redesign train carriages by using a bogie cover (Noise Housing) to reduce noise impact on passengers and residents around train crossings. An initial survey of traffic noise among the public/passengers and literature studies related to ride design and operations have been conducted. A Computational Aeroacoustics (CAA) far-field noise simulation was carried out to compare the noise generated by the collision of train wheels with the train tracks for existing designs and designs with the addition of Noise Housing at varying measurement distances of 3 m, 5 m, 8 m, and 15 m. The initial Noise Housing design using fiber material can reduce noise on average by 19.02 dB. Based on aerodynamic performance testing using Computational Fluid Dynamics (CFD) simulations, it appears that Noise Housing can also significantly reduce aerodynamic drag. It can be concluded that adding Noise Housing can reduce the impact of noise due to train wheel collisions and improve the train’s aerodynamic performance.

The object of this study is the carbon-based organic capacitors, derived from bagasse leaves from the Kebon Agung sugar factory, Malang, Jawa Timur, serving as a sustainable precursor material. The challenge of optimizing the performance of bagasse leaf-based organic capacitors has been a significant barrier in advancing sustainable electronic components. This study aims to develop a quality framework for synthesizing these capacitors by systematically optimizing the parameters using the Taguchi method. Traditional methods often lead to inconsistent performance and high variability, making it difficult to achieve reliable results. By applying the Taguchi orthogonal array, this study identified key factors and optimal levels, effectively reducing experimental efforts while ensuring robust performance. The carbonization of bagasse leaves was conducted using direct combustion with thinner and 70% methanol as liquid burners. Capacitance tests revealed stable values ranging from 0.8897 nF to 0.9281 nF across trials, demonstrating consistent and reproducible behavior. Thermal noise evaluation showed slight temperature variations (69.01°C to 72.01°C), indicating the influence of temperature on electron mobility within the dielectric materials. The systematic approach of the Taguchi method minimized variability and enhanced the capacitors' reliability under varying thermal conditions. The method's focus on robustness and quality control ensured consistent capacitance values and improved overall capacitor performance. Compared to traditional methods, the Taguchi method facilitated a thorough exploration of the design space with fewer experiments. This study underscores the importance of systematic optimization in capacitor design, offering a reliable pathway to integrate sustainable materials into advanced electronic components. The results provide valuable insights into the effects of different parameters on performance metrics, enhancing the development of high-quality organic capacitors

This study aims to assess the accessibility of toilets on the Joglosemarkerto executive train for people with disabilities, especially wheelchair users, using the Universal Design approach. The research method is a mixed method, through direct measurement of toilet dimensions, accessibility checklists based on universal design principles, and online user perception surveys involving 64 respondents, including disabled groups. The Accessibility Index is calculated based on weighting the door, sink, and main toilet room. The study results indicate that the accessibility index category is low, with a score of 22 for the toilet door, 17.5 for the sink, and 24.4 for the main toilet room. The main obstacles are narrow circulation space, insufficient door width, information in Braille, and emergency buttons not being available. Practically, this study encourages operators and policymakers to improve the design of accessible train toilets by involving disabled groups in the design. Theoretically, this study enriches the literature on evaluating public transportation accessibility in Indonesia through the presentation of a replicable universal design evaluation model. The contribution of this study is to map the infrastructure gaps and develop recommendations to improve the inclusiveness of railways in Indonesia and promote equality of access.

This study explores pricing and order interval decisions for competing manufacturers in a circular supply chain. With a growing focus on environmental sustainability in a business, two duopolistically competing manufacturers offer different products to their customers, involving both new and remanufactured products. This research investigates the impact of various products on market demand by considering selling prices and inventories. It highlights how the selling price in the demand function is influenced not only by its price but also by competitors’ prices. Additionally, it emphasizes the pivotal role of the order interval in determining product inventory. This research performs a quantitative method in the operational research. Initially, it structures the demand and profit functions for each manufacturer. By developing a Nash equilibrium model on the game theory, this study determines the optimal decisions for pricing and ordering interval to maximize profit for each manufacturer. The numerical results confirmed that the optimal prices and profits for the manufacturer selling new products (p1=67, π1=1443.96) are higher than the manufacturer (p2=65, π2=1435.22). Meanwhile, the comprehensive sensitivity analysis demonstrates that increasing the selling price (pi=45~85) and order interval (Ti=5.2~6) will reduce the manufacturer’s profit. On the other hand, increasing the competitors’ selling price and order interval will strategically increase the manufacturer’s profit. Furthermore, increasing the wholesale price (wi=35~70) and holding cost (hi=0~15) will decrease the order interval, increase the selling price, and ultimately reduce profit. The managerial insights summarize that it is imperative for a manufacturer to determine the optimal selling price and order interval to gain a competitive advantage when making pricing and ordering interval decisions

The dynamic center of gravity (COG) shift of a train car affects the train running stability. Loss of running stability results in derailments and overturns. This study proposes a novel ticketing algorithm as an effort to prevent derailment and overturn. The algorithm limits the freedom for passengers in seat choosing. Instead, the passengers will be offered recommended seat positions that account for a minimum COG shift. The novel ticketing algorithm implementation was tested in comparison to the existing ticketing algorithm and safety-as-priority (SAP) algorithm. Each algorithm implementation was evaluated and compared analytically through a numerical simulation approach. The dynamic COG shift on a few loading scenarios was evaluated using COG loading shift and COG shift. COG shift evaluation shows novel algorithm has smaller shift than existing algorithm but still bigger than SAP algorithm. The loading shift showing the loss of balance during iterative load addition and load reduction has been reduced through SAP and novel algorithm implementation. In the tested loading scenarios, the Existing algorithm shows (x=2.60x10^-5,-z=3.41x10^-5,y=6.17x10^-5)% shift while SAP shows (x=1.28x10^-5,-z=-2.40x10^-5,y=2.36x10^-5)% and novel algorithm shows (x=1.60x10^-5,-z=3.07x10^-5,y=5.34x10^-5)% Cog shift. The result suggests that the novel algorithm has made it possible to maintain train running stability while noticing the passenger needs. Hence, the running safety of a train can be altered without sacrificing passenger satisfaction.

In the current global era, countries are encouraged to prioritize international trade. Because one of the most important tools and sources of financing in international trade is the foreign exchange reserve for the country itself. Because of the importance of foreign exchange reserves for a country, where foreign exchange reserves always fluctuate, a number of factors can be tested that can affect the position of foreign exchange reserves, namely the amount of export activity. This article was created with the aim of knowing the export potential of fishery products, more precisely the types of shrimp fisheries in Indonesia. Indonesia itself exports shrimp to various countries, one of which is Japan. By using the descriptive method the author tries to explain the importance of agreements in an engagement, especially activities in international buying and selling along with the legal basis regarding international trade activities carried out by the Indonesian state. Then the results of this article study show that exports have a positive and significant effect on foreign exchange reserves for countries that carry out export activities and the importance of agreement clauses in determining which law will be enforced if one of the parties commits a default in order to protect the rights and obligations of the parties, given the activities International trade is prone to acts of abuse of rights and obligations.

Fatigue increases the tendency of poor train driving strategy decision. Decision making in cognitive overload and cognitive underload situation mostly outputs bad decisions. Accordingly, train driver’s cognitive function is required to be sTable during travel so that they can give correct response at a given situation. This study constructs a conceptual framework for cognitive workload management (CWM) of train driver by taking the energy expenses from cognition into the account. This study combines objective and subjective cognitive workload analysis to evaluate train driver duty readiness. The objective load analysis was performed through energy level approximation based on neuronal dynamics simulation from 76 brain regions. The cognitive energy expenditure (CEE) calculated from neuron action potential (NAP) and the ion-membrane current (IMC) from the simulation results. The cognitive load (CL) approximated by converts the continuous time-based CEE to discrete frequency-based CL using Fourier series. The subjective cognitive workload obtained from train simulation results followed by 27 participants. The participants fill the questionnaire based on their simulated journey experience. The results of the evaluation used to build readiness evaluation classifier based on control chart. The control chart evaluation helps the management to determine weekly rest period and daily short rest period treatment base on each train driver workload. The CWM framework allows different recovery treatment to be applied to each train driver. The impact of the CWM application is the performance of train drivers are kept stable. Thus, the CWM framework based on CEE is useful to prevent physical and mental fatigue

Dalam setiap pembangunan suatu proyek konstruksi dibutuhkan perencanaan struktur yang kuat, aman, dan nyaman. Salah satu bagian bangunan untuk mendukung hal tersebut adalah pondasi. Pondasi adalah bagian dari struktur bangunan yang berada paling bawah dan berfungsi untuk beban bangunan yang ada diatasnya. Perencanaan pondasi tiang harus dilakukan dengan seteliti mungkin. Setiap pondasi harus mampu mendukung beban sampai batas keamanan yang telah ditentukan, termasuk mendukung beban maksimum yang mungkin terjadi. Tujuan dari penelitian ini adalah untuk merencanakan pondasi tiang dari tipe pondasinya, keadaan tanah yang digunakan dengan menggunakan metode Meyerhorf dan Luciano Decourt.