• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.13 no.5
• /
• pp.436-442
• /
• 2020

ESS(energy storage system) has recently become an important power source in various areas due to increased renewable energy resources. The more ESS is used, the less the effective capacity of the ESS. Therefore, it is important to manage the remaining useful lifetime(RUL). RUL can be checked regularly by inspectors, but it is common to be monitored and estimated by an automated monitoring system. The accurate state estimation is important to ESS operator for economical and efficient operation. RUL estimation model usually requires complex mathematical calculations consisting of cycle aging and calendar aging that are caused by the operation frequency and over time, respectively. A lightweight RUL estimation model is required to be embedded in low-performance processors that are installed on ESS. In this paper, a lightweight ESS RUL estimation model is proposed to operate on low-performance micro-processors. The simulation results show less than 1% errors compared to the original RUL model case. In addition, a performance analysis is conducted based on ATmega 328. The results show 76.8 to 78.3 % of computational time reduction.

• Journal of KIISE:Information Networking
• /
• v.36 no.5
• /
• pp.413-424
• /
• 2009

Wireless sensor network is based on an event driven system. Sensor nodes collect the events in surrounding environment and the sensing data are relayed into a sink node. In particular, when events are detected, the data sensing periods are likely to be shorter to get the more correct information. However, this operation causes the traffic congestion on the sensor nodes located in a routing path. Since the traffic congestion generates the data queue overflows in sensor nodes, the important information about events could be missed. In addition, since the battery energy of sensor nodes exhausts quickly for treating the traffic congestion, the entire lifetime of wireless sensor networks would be abbreviated. In this paper, a new congestion control method is proposed on the basis of genetic algorithm. To apply genetic algorithm, the data traffic rate of each sensor node is utilized as a chromosome structure. The fitness function of genetic algorithm is designed from both the average and the standard deviation of the traffic rates of sensor nodes. Based on dominant gene sets, the proposed method selects the optimal data forwarding sensor nodes for relieving the traffic congestion. In experiments, when compared with other methods to handle the traffic congestion, the proposed method shows the efficient data transmissions due to much less queue overflows and supports the fair data transmission between all sensor nodes as possible. This result not only enhances the reliability of data transmission but also distributes the energy consumptions across the network. It contributes directly to the extension of total lifetime of wireless sensor networks.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.4
• /
• pp.469-486
• /
• 2017

Economy-based urban redevelopment is the main priority in Malaysia, but has resulted in social problems such as gentrification, loss of heritage and identity, inequity, etc. Hence, it is crucial for the government to seek other alternatives rather than being solely reliant on urban redevelopment. Neighborhood renewal is a strategy involving the integration of redevelopment, rehabilitation, revitalization and preservation that aims to improve deprived areas using a more holistic approach. The aim of this paper is to review the neighborhood renewal policies in developed countries and to identify those elements that can be adopted in Malaysia. This study is conducted via a literature review. It was found that neighborhood renewal which integrates people-based, place-based and system-based policies highlights the importance of diversity, thereby aiming for resource optimization, community engagement and urban governance with the focal point of the fair, equity and systematic provision of resources. This paper concluded that neighborhood renewal in Malaysia should be initiated by locals with an emphasis on real local participation and a sustainable funding system. The government and local authorities should be observers rather than implementers.

• Journal of Energy Engineering
• /
• v.28 no.3
• /
• pp.18-25
• /
• 2019

In this study, in order to solve the problem of the program of calculating code input by experienced users in the power generation, the wide area energy network research group developed the local heating operation analysis program EntPLAN, which can be easily used by anyone, including scalability, with domestic technology. Therefore, the Commission intended to compare the heat sources, heat demand, and the results of operation of the combined heat plant (CHP) on the energy network through simulation with the EnetPLAN and the program A on the market. The results showed that the heat and power output on the energy network of the EnetPLAN and A programs were mostly similar in pattern in the simulation results of the heat supply and the operation method of the accumulator. This enabled the application of the simulation for the various operation modes of the cogeneration facilities existing on the energy network. It is expected that EntPLAN, which was developed with domestic technology, will be easily applied in the field in the future and will present efficient operation simulation results.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.3
• /
• pp.285-290
• /
• 2019

This study aims to compare the energy consumption characteristics of high-rise and general apartments and propose policy implications in Incheon City where high-rise apartments are planned. The method of analysis is to select the cases, to conduct field survey, drawing review, analysis of Electric Architectural administration Information System. The study derived the current status of energy consumption in high-rise and general apartment complexes located in the same region, Yeonsu-gu Incheon City, and performed comparative analysis on their characteristics. First, electrical energy in the high-rise apartment complexes was consumed excessively, by 1.63 to 2.5 times more than that of the general apartment complexes. Second, the gas energy usage in the high-rise apartment complexes was higher than that of the general complexes, by 1.09 to 1.2 times. Third, the energy consumption per unit area in the high-rises was also higher, by 1.042 to 1.3 times. As individual elements such as incomes, living standards, and life patterns of the residents affect energy consumption, the high-rise apartment complex consumed more energy per unit area than the general apartment complex did. However, this study did not consider the elements of energy expenditure and satisfaction level, which are the limitations of this research.

• Journal of the Korean Electrochemical Society
• /
• v.21 no.4
• /
• pp.80-87
• /
• 2018

Safety issues in Li-ion battery system have been prime concerns, as demands for power supply device applicable to wearable device, electrical vehicles and energy storage system have increased. To solve safety problems, promising strategy is to replace organic liquid electrolyte with non-flammable solid electrolyte, leading to the development of all-solid-state battery. However, relative low conductivity and high resistance from rigid solid-solid interface hinder a wide application of solid electrolyte. Composite electrolytes composed of organic and inorganic parts could be alternative solution, which in turn bring about the increase of conductivity and conformal contact at physically rough interfaces. In our study, composite electrolytes were prepared by combining poly(ethylene oxide)(PEO) and $Li_7La_3Zr_2O_{12}$ (LLZO). The crystallinity, morphology and electrochemical performances were investigated with the control of LLZO contents from 0 wt% to 50 wt%. From the results, it is concluded that optimum content and uniform dispersion of LLZO in polymer matrix are significant to improve overall conductivity of composite electrolyte.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.6
• /
• pp.469-476
• /
• 2021

An electronic attack (EA) system is an essential weapon system for performing electronic warfare missions that contain signal tracking and jamming against multiple threats using electromagnetic waves, such as air defense radars, wireless command and communication networks, and guided missiles. The combat effectiveness can be maximized, and the survivability of militarily protecting combat power can be enhanced through EA mission operations, such as disabling the functions of multiple threats. The EA system can be used as a radio frequency jamming system to respond to drone attacks on the core infrastructure, such as airports, power plants, and communication broadcasting systems, in the civilian field. This study examined the criteria for classification according to the electronic attack missions of foreign EA systems based on an aviation platform. The foreign R&D trends by those criteria were investigated. Moreover, by analyzing the R&D trends of domestic EA systems and future battlefields in the domestic security environments, this paper proposes technological development plans of EA systems suitable for the future battlefield environments compared to the foreign R&D trends.

• Convergence Security Journal
• /
• v.20 no.4
• /
• pp.187-196
• /
• 2020

In order to manage information security risk, various information security level evaluation and information security management system certification have been conducted on a larger scale than ever. However, there are continuous cases of infringement of information protection for companies with excellent information security evaluation and companies with excellent information security management system certification. The existing information security risk management methodology identifies and analyzes risks by identifying information assets inside the information system. Existing information security risk management methodology lacks a review of where cyber threats come from and whether security devices are properly operated for each route. In order to improve the current risk management plan, it is necessary to look at where cyber threats come from and improve the containment level for each inflow section to absolutely reduce unnecessary cyber threats. In addition, it is essential to measure and improve the appropriate configuration and operational level of security equipment that is currently overlooked in the risk management methodology. It is necessary to block and enter cyber threats as much as possible, and to detect and respond to cyber threats that inevitably pass through open niches and use security devices. Therefore, this paper proposes additional evaluation items for evaluating the containment level against cyber threats in the ISMS-P authentication items and vulnerability analysis and evaluation items for major information and communication infrastructures, and evaluates the level of security equipment configuration for each inflow.

• Journal of Software Assessment and Valuation
• /
• v.16 no.1
• /
• pp.55-63
• /
• 2020

Lasers for optical broadband communication systems should have excellent frequency selectivity and modal stability. DFB lasers have low lasing frequency shift during high speed current modulation. In this paper, when a refractive index grating and a gain grating are simultaneously present in a DFB laser having a wavelength of 1.55 ㎛, the dielectric film is coated so that reflection does not occur on the right mirror surface, so that ρ_r=0. For the first mode, which requires a minimum gain at the threshold, the beam distribution of the oscillation mode in the longitudinal direction and the radiated power ratio P_l/P_r were analyzed and compared for the cases of the phase of ρ_l=π and π/2. If the phase of ρ_l=π, in order to obtain a low threshold current and high frequency stability, κL should be greater than 8. In the case of the phase of ρ_l=π/2, for low threshold current, κL is necessary to be 1.0, where the oscillation frequency coincides with the lattice frequency. DFB lasers with an anti-reflection coated mirror have excellent mode selectivity than 1.55um DFB lasers with two mirror facets

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.12
• /
• pp.17-27
• /
• 2022

In this paper, ED-H algorithm, an optimal real-time scheduling algorithm dealing with the characteristics of the integrated energy harvester system with a capacitor, is extended to satisfy the time constraint under the blackout state which is a deliberate power-off state by an intelligent power management unit adopted in the system. If the power supply system does not have enough energy, it temporarily shuts off the power supply to protect the circuit and capacitor and resumes the supply again when the capacitor is fully charged, which may delay the task execution during these blackout states by calculating the time according to the occurrence of the events. To mitigate the problem, even if task execution is delayed by the original ED-H algorithm, the remaining time of the subsequent time units no longer can afford to delay the execution of the task is predicted in the extended algorithm and the task is forced to be scheduled to meet the time deadline. According to the simulation results, it is confirmed that the algorithm proposed in this paper has a high scheduling performance increase of 0.4% to 7.7% depending on the characteristics of the set of tasks compared to the ED-H.