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The rapid development of smartphone technology today creates challenges for consumers and manufacturers in determining an objective price range based on highly varied technical specifications. This study aims to implement the Random Forest algorithm in classifying smartphone price ranges into four main categories, namely low, mid-range, high, and flagship. The research method was carried out systematically through the stages of loading a dataset of 2,000 entries, exploratory data analysis (EDA) to ensure data integrity, and model training with a training and testing data split of 80:20. The results showed that the Random Forest model achieved a significant overall accuracy rate of 89%. Based on feature importance analysis, it was found that RAM capacity was the most dominant determining factor, contributing 47% to prediction accuracy, followed by battery power and screen resolution as supporting features. These findings have strategic implications for manufacturers to prioritize memory capacity upgrades in determining product pricing in the market, as well as providing guidance for consumers in assessing the fairness of a device's price based on its technical capabilities.

The problems in rice fields are complex and varied, depending on geographic location, rice variety, and growing season. Pests often cause serious economic losses. The Solar Sonic Repeller is an innovative portable pest control device designed to address pest problems by utilizing renewable energy, specifically solar energy. This product aims to offer an environmentally friendly and efficient solution. It works by emitting ultrasonic sound waves with a frequency of 30,000–40,000 Hz. The device's advantages lie in its portability and energy independence, thanks to the use of a charging module powered by an integrated photovoltaic (PV) panel with automatic battery charging during the day. The first test measured the output frequency using an oscilloscope to verify that the oscillator circuit produced waves at the specified frequency. The second test measured the device's effectiveness by examining the pest response to the device at various distances. This test was effective within a maximum radius of approximately 14 m from the center point, covering a rice field area of ​​250 m2.

Indonesia has extraordinary resources and potential in developing renewable energy sources (RES), but various obstacles must be overcome in implementing RES. The purpose of this study is to analyze the gap in the application of RES. This gap includes energy knowledge, community participation, battery waste management, service quality, regulation, and legal policy. This study uses a mixed-methods approach, by conducting a structured questionnaire in quantitative data collection, while qualitative data collection through special interviews, focused group discussions, and conducting policy regulation analysis. The results show that 62% of people do not understand RES, 28% are involved in project planning, and 74% are unaware of SOP (standard operating procedures) regarding battery waste recycling. The results of the correlation analysis reveal a positive relationship between the level of knowledge and interest in RES (R = 0.56). Also, the developed community-based participation model includes initial involvement, transparency of information, and local incentives. These findings further strengthen the compatibility of the innovation diffusion theory, planned behavior theory, SERVQUAL, and the theory of public interest. This study will make a practical contribution through evidence-based strategies in increasing resilience, especially for policymakers and energy service providers. The impact of the policy aspects includes the need for large reforms, education, public campaigns, and the realization of battery waste management systems. This study also provides an opportunity for further study by expanding the geographical scope and related industrial sectors.

Purpose – Purpose This is for explore interconnection strategic between system energy and defense in support resilience national with propose draft paradigm energy dual role paradigm This positioning energy No only as protected objects​ from threat external, but also as subject strategic support​ operation military through energy renewable, implementation network smart, and technology storage battery. Design/ methodology / approach – Research This use approach review library systematic (SLR) for synthesize findings academic and reports policy from three year lastly, which involves source journal national (SINTA indexed) and international (Elsevier, Springer, IEEE, etc.), with focus on intersection between resilience energy and defense strategy national. Findings – Review This disclose that infrastructure resilient energy​ increase capability defense, while system formidable defense​ ensure continuity supply energy national research​ This propose an integrative model consisting of from three layer strategic: integration policy national (between RUEN and RENSTRAHAN), development infrastructure green and digital, and development capacity source Power man together. Framework Work integrative This strengthen reciprocal resilience​ between sector energy and defense. Implications practical – The makers policies, institutions military, and stakeholders interest energy pushed for together implementing synchronized strategies, integration curriculum and investment in infrastructure digital energy use reach resilience national term long in face uncertainty geopolitics and environment. Originality / Value – Study This introduce framework Work new paradigm energy role double in defense national, which provides runway theoretical and practical for integrate transition energy sustainable with planning defense strategic. Study This contribute in a way conceptual for bridge gap between policy energy and defense strategy, especially in context threat hybrids and vulnerabilities system cyber-physical.

This research presents the design, development, and implementation of a mini smart car prototype that operates using Internet of Things (IoT) technology. The system is built around the ESP8266 microcontroller (Amica version), which functions as the core processing unit responsible for handling Wi-Fi communication and data processing. The motion of the car is controlled by an L298 motor driver module that regulates the operation of DC motors. The entire system is powered by a 3.7-volt rechargeable battery, ensuring portability and energy efficiency. The study discusses in detail the hardware configuration, software programming, and integration of IoT-based control through a web or mobile interface. Functional testing of the prototype, named MINIOT, focuses on evaluating the responsiveness, stability, and reliability of remote control operations. The results are expected to show that the system can effectively receive and execute user commands while transmitting real-time telemetry data, such as motor status and connection indicators. This project demonstrates the feasibility of low-cost IoT-based automation for small-scale robotic applications.

This research presents the design, development, and implementation of a mini smart car prototype that operates using Internet of Things (IoT) technology. The system is built around the ESP8266 microcontroller (Amica version), which functions as the core processing unit responsible for handling Wi-Fi communication and data processing. The motion of the car is controlled by an L298 motor driver module that regulates the operation of DC motors. The entire system is powered by a 3.7-volt rechargeable battery, ensuring portability and energy efficiency. The study discusses in detail the hardware configuration, software programming, and integration of IoT-based control through a web or mobile interface. Functional testing of the prototype, named MINIOT, focuses on evaluating the responsiveness, stability, and reliability of remote control operations. The results are expected to show that the system can effectively receive and execute user commands while transmitting real-time telemetry data, such as motor status and connection indicators. This project demonstrates the feasibility of low-cost IoT-based automation for small-scale robotic applications.

Air pollution and oil reserves are two major issues in the technological development of the automotive industry. Air pollution is caused by gases from burning fossil fuel vehicles. In 2018-2019 Indonesia experienced a drastic decrease in petroleum resources by 49.8%. To overcome this problem, many researchers have conducted research on electric vehicles, including electric bicycles. This study aims to determine the effect of distance and load on BLDC motor power consumption on a prototype e-bomber electric bicycle designed for all terrains such as rocky, sandy, and muddy, and has a large battery capacity, low power consumption, and an electric motor with good speed and torque. This research uses a pseudo-experimental method with a quantitative approach. Tests were carried out on e-bomber electric bicycles with distances of 3 km, 5 km, and 8 km and loads of 60 kg, 70 kg, and 80 kg with a speed of 25 km / h. The results showed that there was an influence of distance and load on the e-bomber electric bicycle. The results showed that there was an effect of distance and load on BLDC motor power consumption with the results of graph analysis and two-way ANOVA tests conducted and the lowest average power consumption of 500 watts at a distance of 3 km and a load of 60 kg, while the highest average power consumption was 522.5 watts at a distance of 8 km and a load of 80 kg.

Enhancing the efficiency of renewable energy on ships is crucial for reducing dependency on fossil fuels. This research employs the Research and Development (R&D) method, aiming to design and implement a solar panel optimization system for battery charging, with a focus on increasing power efficiency and providing real-time performance monitoring. The system is designed using Maximum Power Point Tracking (MPPT) technology to maximize the solar panel's power output. A 200Wp solar panel with dimensions of 1290 x 760 x 30 mm was utilized. Static testing results show that the deployed sensors possess a high degree of accuracy, with an average error of 0.71% for the temperature sensor and only 1.81% for the light sensor used to monitor environmental conditions. Dynamic and system integration tests prove that the MPPT implementation significantly increases power output efficiency by 30.83% compared to a system without MPPT. Furthermore, the system with MPPT charges the battery approximately 27% faster. Additionally, the developed Modbus protocol-based monitoring system enables comprehensive and remote monitoring of key parameters such as voltage, current, temperature, and light intensity via a cloud database. Data communication reliability tests confirmed the system's capability to transmit entire data packets to a Google Sheets database at a periodic interval of 15 seconds without failure. Based on these results, the developed solar panel optimization system is feasible for implementation in maritime environments to enhance the utilization efficiency of renewable energy and the operational reliability of onboard systems.

The use of buck converters as DC step-down voltage regulators is increasingly important in various power electronics applications. However, the quality of the output voltage is often disturbed by the presence of ripple, which is influenced by variations in the duty cycle. This study aims to analyze the effect of duty cycle variations on the output voltage and ripple of a buck converter using MATLAB/Simulink simulation. The method used is quantitative simulation by varying the duty cycle from 10% to 90% in a buck converter circuit with fixed parameters: input voltage 30 V, switching frequency 40 kHz, inductor 176.25 μH, and capacitor 44.33 μF. The simulation results show that the output voltage is proportional to the duty cycle, increasing from 3.245 V at D=10% to 26.82 V at D=90%. The highest ripple occurred at D=40% with a value of 0.07 V, while the lowest ripple was at D=50% with a value of 0.0003 V. These findings indicate the existence of an optimal operating point where the system works most stably. This study provides practical guidance in designing efficient and stable buck converters for applications such as battery charging and renewable energy systems.

The availability of electrical energy is one of the important factors during learning activities. However, because the electrical system can be said to be very complicated, starting from the generator center all the way to the consumer, there will most likely be a disruption that causes the flow of power to the consumer to be cut off. One of the factors that affect includes environmental factors, maintenance and other factors, so that the learning process is slightly hampered. The purpose of this research is to maintain electricity supply by automatically switching sources and utilizing renewable energy as a reserve for lighting students' practice rooms. Therefore, a system is needed that automatically regulates the switching of primary sources to backup sources. Automatic Transfer Switch or ATS is a device that automatically switches the main power source from PLN to a backup source such as solar panels by setting the time using Time Delay Relay (TDR). TDR functions to regulate the duration of the power source change operation to meet load needs, especially on small loads such as student practice rooms with a voltage of 220 Volts in one language. The advantage of this system is that it is able to automatically switch electricity supply between PLN and Solar Panels with a controlled time lag. The research method involves the installation of electrical panels and Solar Panels using Solar Charger Controller or SCC, Inverter devices. At the time of the study, the adjustment of the TDR setting to set the time lag on the ATS. SCC settings are carried out to obtain Inputs and Outputs in the optimal battery charging process where the measurement results show that When the load of the incandescent lamp is increased from 50Watt to 300Watt, the current increases from 4.47A to 25.2A, while the voltage decreases from 11.7V to 9.8V. In conclusion, the greater the load, the solar panel voltage decreases and the current increases. The results of the study show that the implementation of the automatic transfer switch system is able to automatically switch the electricity supply between PLN and Solar Panels with a controlled time lag.

This community service program was implemented to overcome the limited technical capacity of teachers and students at SMK Negeri Jambu in mastering the installation and programming of battery-based electric vehicles, which is a crucial skill in preparing competent human resources for the rapidly evolving green vehicle industry. The program specifically aimed to enhance participants’ knowledge and skills in several key areas, including the installation of electric motor control systems, management of battery energy, and maintenance of essential electric vehicle components. To achieve these goals, the activities were carried out using a blended method that integrated lectures, demonstrations, and direct hands-on practice, supported by continuous mentoring and systematic evaluation. In addition, QR Code–based learning resources were incorporated to provide participants with quick and efficient access to digital instructional materials, allowing for more flexible and independent learning. The evaluation results revealed significant progress in both the theoretical understanding and practical abilities of the participants. They were able to demonstrate improvements not only in operating and maintaining electric vehicle systems but also in identifying problems and performing troubleshooting independently. These findings suggest that the program effectively contributed to building sustainable competencies for teachers and students, equipping them with relevant skills aligned with the needs of the green automotive industry, while also promoting technological adaptation and innovation in vocational education.

This study analyzes the potential use of solar cells as a renewable energy source on the MV SARI INDAH. With the increasing demand for energy and the negative environmental impacts of fossil fuels, solar cells provide a promising eco-friendly alternative. The research focuses on developing a prototype system to charge batteries using solar power, converting DC power into AC for ship operations. The methodology includes measuring sunlight intensity, current, and output voltage, while also calculating the battery capacity and the ship’s electrical load. Tests were conducted at various tilt angles, with data recorded hourly over two days to assess performance. The results show that a 75° tilt angle yields the highest voltage, current, and power output when compared to other angles. Based on these findings, the study recommends installing solar panels at a 75° angle on the compass deck. The system design utilizes two panels positioned opposite each other, forming a 150° angle to optimize energy capture. This setup is capable of supplying power to key areas on the ship, such as seven lamps in the E/R 2nd Deck, Control Room, Emergency Generator Room, and CO₂ Room. The system is designed to meet the total daily energy demand of approximately 1,400 Wh, which can be efficiently fulfilled by eight solar cells rated at 50 Wp each, providing a sustainable and efficient energy solution for the vessel.

The need for environmentally friendly marine transportation continues to increase, especially in tourist areas such as Penyengat Island, Tanjungpinang, Riau Islands. In the local context, the design of electric boats has not been widely developed for small islands in Indonesia, even though the potential and urgency for its application is very high. Geographical constraints, limited charging infrastructure, and a lack of technical data are the main obstacles. This research focuses on the design and construction of an electric-powered tourist boat prototype with an asymmetrical catamaran hull type as an effort to support a sustainable transportation system. The boat design applies an asymmetrical catamaran hull configuration to improve sailing stability and energy efficiency. The propulsion system is controlled via a wireless PS2 joystick integrated with an ESP32 microcontroller, supported by a 24V DC motor powered by lithium-ion batteries and solar panels as a supplement. Test results show that the boat can operate stably with remote control, good energy efficiency, and zero emissions during operation. Some technical challenges encountered include limited operational duration due to battery capacity and high sensitivity of electronic components to water exposure. Overall, this prototype has great potential for further development as an environmentally friendly alternative for maritime transportation system. The stable catamaran hull design provides advantages in terms of comfort and safety, especially in calm or shallow waters. The electric propulsion system used has proven to be efficient and responsive, supported by a remote control mechanism that is easy to operate via a wireless joystick

As an archipelagic country, Indonesia has significant potential for the utilization of renewable energy, particularly wind energy in maritime areas with low wind speeds (3–6 m/s). This study aims to design and test a vertical Savonius wind turbine system equipped with a Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) algorithm as a power source for shipboard water heating systems. The research method applied is Research and Development (R&D), integrating several components such as a DC generator, full-wave bridge rectifier, INA219 current sensor, anemometer cup sensor, ESP32 microcontroller, and a monitoring interface utilizing Google Spreadsheet and a 20x4 LCD. The system was tested under two operating conditions: without MPPT and with MPPT. The experimental results show that the application of the MPPT algorithm successfully increased power output by up to 272.64% while maintaining voltage stability despite varying wind speeds. Nevertheless, the average output power of 2.605 W remained insufficient to meet water heating requirements within a short time. For example, charging a 12V 50Ah battery would require approximately 9.6 consecutive days of operation, highlighting the system’s limitations in high-demand scenarios. Despite these constraints, the findings demonstrate that the vertical Savonius wind turbine integrated with MPPT has strong potential as a clean and environmentally friendly alternative energy solution for maritime applications, particularly for small-scale onboard electrical loads. This study contributes to renewable energy utilization in the shipping sector and provides a foundation for further technological development and optimization.

Tourism is one of the most important economic sectors in the world, contributing significantly to state revenue and improving people's welfare. The tourism industry has grown rapidly in recent decades, with the number of international tourists continuing to increase. The general objective of this study is to develop a deeper knowledge and understanding of the impact of uncontrolled tourism on the sacredness of Bali's nature and culture, as well as strategies for developing sustainable tourism in Bali. The type of research used by the author in examining the problems in this study is normative juridical research. The conclusion of this study is a legal review of the protection of natural and cultural heritage in Bali Province is regulated in several laws and regulations such as Law No. 5 of 1990 concerning the Conservation of Biological Natural Resources and Ecosystems. In addition, cultural protection in Bali has also been regulated in several laws and regulations such as Law No. 11 of 2010 concerning Cultural Heritage. This legal review will also discuss the implementation of laws and regulations related to the protection of natural and cultural heritage in Bali. The Bali provincial government's policy on the protection of natural and cultural heritage, namely the policy on the protection of natural heritage is regulated in the Governor's Regulation or Pergub No. These include Law No. 97 of 2018 concerning the Limitation of Single-Use Plastic Waste, Governor Regulation No. 45 of 2019 concerning Bali Clean Energy, Governor Regulation No. 48 of 2019 concerning the Use of Battery-Based Electric Motorized Vehicles, and Governor Regulation No. 8 of 2019 concerning Organic Farming Systems. Cultural heritage protection policies are regulated by Law No. 10 of 2010 concerning Tourism, Regional Regulation No. 2 of 2023 concerning the Bali Provincial Spatial Plan (RTRWP), the Designation of Cultural Heritage Areas in Bali, such as Ulun Danu Batur Temple and Lake Batur, the Subak Cultural Landscape and Temples in the Pakerisan Watershed, and others.

Batteries are the primary component in electric motorcycle propulsion systems, playing a crucial role in storing and supplying energy. However, batteries have a limited lifespan, potentially becoming waste after their useful life. Battery waste is categorized as hazardous and toxic waste (B3) because it contains heavy metals and chemical compounds that can negatively impact human health and the environment if not managed properly. As the adoption of electric motorcycles increases in Indonesia, particularly in the Special Region of Yogyakarta (DIY), the issue of battery waste management is becoming increasingly important. Currently, there are no electric motorcycle manufacturers openly willing to manage post-life battery waste, particularly through recycling activities. This situation creates a gap that informal actors could potentially exploit. Informal actors often possess flexibility and basic technical skills, but their capacity to manage battery waste safely and sustainably still needs to be mapped and strengthened. This study focused on mapping the potential capabilities of informal actors in the Special Region of Yogyakarta by 2025. The results indicate that the potential for informal actors capable of providing battery repair services is only around 1%. This figure is very small and therefore insufficient to support future battery waste management needs. Therefore, multi-stakeholder support is needed, from the government and manufacturers to the community, to encourage capacity building among informal actors. This effort is crucial to anticipate the success of the government's 2030 target for electric vehicle conversion, while also ensuring environmental sustainability.

The development of electric motor vehicles drives the need for efficient, stable, and reliable energy storage systems. This study aims to compare the performance of three types of batteries commonly used in electric motorcycles, namely LiFePO4 (Lithium Iron Phosphate), Li-Ion (Lithium Ion), and Lead Acid (Lead Battery). The parameters tested include energy efficiency, capacity, and performance during the starting process. The test method was carried out for 60 minutes through a charging and discharging process (charge-discharge), using a pzem-015 measuring instrument and a multimeter to monitor the current, voltage, input/output power, and battery capacity. The test results show that the LiFePO4 battery provides the best performance. This battery has the highest efficiency and capacity, reaching 1430 mAh, with a stable average efficiency in the range of 50–60%. In addition, LiFePO4 also produces the highest current and voltage when used for starting, making it very reliable for the initial needs of electric motorcycle operation. Meanwhile, the Li-Ion battery recorded a high initial efficiency of up to 87.27%, but this efficiency decreased and then stabilized at 72%, with a recorded capacity of 1360 mAh. Although its efficiency is quite good, its long-term stability is still below that of LiFePO4. Meanwhile, the Lead Acid battery showed the lowest performance. Its efficiency continued to decline to only 26.3% at the end of the test. Its capacity is 1380 mAh, but the increase is unstable, indicating inconsistencies in power storage and discharge. Based on these results, LiFePO4 batteries are recommended as the main choice for electric motorcycles because they excel in aspects of energy efficiency, performance stability, and long-term durability.

This study aims to examine whether there is a correlation between the hedonistic lifestyle of STIE Bima students and their aspiration to purchase an iPhone. The hedonistic lifestyle, which focuses on the pursuit of pleasure and instant gratification, often drives individuals to acquire luxury and prestigious items such as the iPhone. However, issues related to the product, such as fast battery drainage, poor performance, and blocked IMEI, have been documented by users. These problems can affect the brand image and purchasing intentions. Furthermore, the temporary nature of hedonistic pleasure causes consumers to continually seek new products to fulfill their emotional desires, which could influence their purchasing decisions. Additionally, negative perceptions of a product’s value, price, or quality may lead consumers to hesitate in making a purchase. Therefore, it is essential to understand how the hedonistic factor interacts with the intention to buy a specific product, particularly among students who are often the primary consumers of electronic products like the iPhone. This study uses a quantitative method with an associative research strategy to explain the relationship between a hedonistic lifestyle and purchase intention. A total of 96 STIE Bima students were selected as the sample, using the Lemeshow algorithm. Data were collected through questionnaires, direct observation, and literature review. Data analysis was performed using various statistical methods, including validity and reliability tests, classical assumption tests (such as normality, multicollinearity, heteroscedasticity, and autocorrelation), as well as multiple linear regression analysis. t-tests (both partial and simultaneous) were used to test the impact of each variable on purchase intention. Correlation coefficients were used to measure the strength of relationships between the variables studied. The results of this study are expected to provide insights into how a hedonistic lifestyle influences iPhone purchasing decisions among students.

The Message Queue Telementary Transport (MQTT) protocol is able to adjust the sending and receiving of messages to monitor in accordance with the user's preferences because the sending and receiving of messages is topic based on a specified topic, making it necessary to routinely monitor the condition of patients who have been diagnosed with heart problems from a distance. With the aim to perform a Quality of Service (QoS) analysis with throughput, delay, and packet loss parameters using Unshielded Twisted Pair internet transmission media (UTP) and Wireless, the goal of this research is to design and implement (MQTT) a heart rate monitoring device with an EKG module as a sensor and ESP32 as a microcontroller. On the Ubidots website, EKG signals are transmitted over the internet and shown in real time. QoS analysis is performed using the Wireshark application. Data was collected on two scenarios at intervals of 30 minutes, 1 hour, 2 hours, 5 hours, 8 hours, 12 hours, 18 hours, and 23 hours. The throughput, latency, and packet loss metrics used in this study's results cause different value variations; these are influenced by the weather, internet bandwidth, computer, and router specifications. According to testing, the tool is portable and has a 3000mAh battery, but it has the restriction that it can only be used with reliable internet and bandwidth.

The amount of load on the vehicle requires a balance current and voltage. To fullfill the requirement, vehicle use a energy stroage media called lead acid battery. Although the lead acid battery have a impaccable durability, the performance will be decrase as long as use, especially in term of power and durability. The downgrade performance from the battery make high cost replacement, meanwhile there is a change to fix the battery. One of the methode to fix is replace the cell and added H₂SO₄ electrolyte concentrat variation. This research intend to examine repairment effectivity and electrolyte concentrat variation on power for used lead acid battery NS40 type. H₂SO₄ electrolyte that used is 30%,40% and 45%  examine with 5 static dummy load 1 Ω 100 W pararrel circuit. Each electrolyte examine 60 times to obtain performance and durability data. The results show that increasing the concentration of H₂SO₄ has a significant effect to produce the voltage and current. At 30% concentrate, an average voltage is 9.8 V and the current is 30.125 A at 40% concentarte, the voltage is 10.18 V and the current is 32.731 A and at 45% concentrate, the voltage is 10.19 V and the current 33.375 A.