• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.95-102
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• 2014

In this paper, we propose the high speed PLC-based automatic control system for a smart LED streetlight. The proposed the automatic control system were constructed of a power line modem part and monitoring part, streetlight controller part for the high speed communication frequency band and streetlight ballasts characterization and real-time remote control using a high-speed PLC network, and it was designed to meet to lighting grades conditions of KS road lighting standards. The proposed automatic control system were easy monitoring of the power consumption using PC through to the comparison result of the existing streetlight system. As a result, it was confirmed to the possibility of efficient operation for the real-time monitoring and maintenance by induction of reasonable power consumption through to the LED streetlight state checking and remote-control. In addition, we proved to improvement of expected effects for the power cost savings, the energy efficiency, and streetlight differentiation and advanced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.602-608
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• 2020

Development of Internet technology and the spread of various smart devices provide a convenient computing environment for people, which is becoming common thanks to the Internet of Things (IoT). However, attacks by hackers have caused various problems, such as leaking personal information or violating privacy. In the IoT environment, various smart devices are connected, and network attacks that are used in the PC environment are occurring frequently in the IoT. In fact, security incidents such as conducting DDoS attacks by hacking IP cameras, leaking personal information, and monitoring unspecified numbers of personal files without consent are occurring. Although attacks in the existing Internet environment are PC-oriented, we can now confirm that smart devices such as IP cameras and tablets can be targets of network attacks. Through performance evaluation, the proposed protocol shows 11% more energy efficiency on servers than RSA, eight times greater energy efficiency on clients than Kerberos, and increased efficiency as the number of devices increases. In addition, it is possible to respond to a variety of security threats that might occur against the network. It is expected that efficient operations will be possible if the proposed protocol is applied to the IoT environment.

• Journal of Energy Engineering
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• v.29 no.2
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• pp.68-78
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• 2020

According to the new climate change agreement, technology development to reduce greenhouse gases is actively conducted worldwide, and research on energy efficiency improvement in the field of power generation and transmission and distribution is underway [1,2]. Economic analysis of the operation method of storing and supplying surplus electricity using energy storage devices, and using energy storage devices as a frequency adjustment reserve power in regional cogeneration plants has been reported as the most profitable operation method [3-7]. Therefore, this study conducted an economic analysis for the installation of energy storage devices in the combined heat and power plant in the Czech Republic. The most important factor in evaluating the economics of battery energy storage devices is the lifespan, and the warranty life is generally 10 to 15 years, based on charging and discharging once a day. For the simulation, the ratio of battery and PCS was designed as 1: 1 and 1: 2. In general, the primary frequency control is designed as 1: 4, but considering the characteristics of the cogeneration plant, it is set at a ratio of up to 1: 2, and the capacity is simulated at 1MW to 10MW and 2MWh to 20MWh according to each ratio. Therefore, life was evaluated based on the number of cycles per year. In the case of installing a battery energy storage system in a combined heat and power plant in the Czech Republic, the payback period of 3MW / 3MWh is more favorable than 5MW / 5MWh, considering the local infrastructure and power market. It is estimated to be about 3 years or 5 years from the simple payback period considering the estimated purchase price without subsidies. If you lower the purchase price by 50%, the purchase cost is an important part of the cost for the entire lifetime, so the payback period is about half as short. It can be, but it is impossible to secure profitability through the economy at the scale of 3MWh and 5MWh. If the price of the electricity market falls by 50%, the payback period will be three years longer in P1 mode and two years longer in P2 and P3 modes.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.98-103
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• 2004

Recently, a New Great Harbour Bridge between Mokpo City and Koha Island is planned to be built across Mokpo Inner Harbour, and Namak New Town is under construction adjacent to Mokpo. Citizels' concorn of and participation in 「Campaign for Shaping Mokpo into Beautiful Seaport」 are necessary to match the view of Mokpo harbour with natural scenery beautifully and with marine environment harmoniously. Citizens'ㄹ levels of consciousness of coastal and marine environment were ascertained through questionnaire surveys of local citizenry attitudes and opinions, and citizenry action plans for the conservation of coastal and marine environments around Mokpo harbour are suggested on the basis of the results of questionnaire surveys. Citizens' voluntary participations in local policy for the control of marine wastes production and in a campaign for the collections of marine debris and wastes around beaches and coastal areas are required. The operation of municipal sewage treatment plants is to be performed effectively and efficiently, and to be monitored and evaluated periodically by the general public, the local federation for environmental movement or NGO. The development and performance of marine environmental education programs and an enlightenment campaign for environment preservation are to be incessantly done in cooperation with local residents. Only when local government of Mokpo collects the public opinions and continues to shape Mokpo into international beautiful seaport in the direction of a reflex of public opinion, coastal and marine environment around Mokpo harbour can be kept in good condition with citizens' positive participation in citizenry long-term practical action plans for environment conservation.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.265-274
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• 2016

In this study, the system was composed of the booster chopper and the power converter, which is a pulse width modulation (PWM) voltage inverter using a hybrid power generation system solar cell energy and wind force, Furthermore, in order to compensate the PWM voltage type inverter was linked with the general commercial power source, and through a normal operation of energy storage system (ESS), the system operated the LED Taxi Light by Wavelength according to Meteorological Changes at the airport in an efficient manner. The performance of the system was compared with the solar cell characteristics specification. In addition, for phase synchronization with the PWM voltage type inverter, the grid voltage was detected so as to operate the grid voltage and inverter output in the same phase and to connect the surplus electric power with the system. Finally, by developing a control circuit at the same time from which an excellent dynamic characteristics can be obtained through applying to the airport runway taxi light, it was concluded that a variety of taxi light can be pursued.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.317-317
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• 2015

강이나 하천에 이수 및 치수의 목적으로 소규모 댐이나 보 등의 수리구조물을 설치한다. 수리구조물의 상하류부에는 하천 하상의 극심한 침식인 국부세굴현상을 방지하여 수리구조물의 안정성을 확보하기 위해 하상보호구조물을 설치하는데, 특히 하류부에 설치하는 하상보호구조물에는 크게, 다양한 형식과 크기의 물받이공, 에너지 감세공, 그리고 끝턱구조물 등이 이에 속한다. 지금까지 국내 외 수리구조물 설계지침에서는 하상보호공의 적절한 길이규모를 산정하기 위한 다양한 공식이 개발 및 적용되었지만, 최근 들어 다양한 목적을 위해 복잡해진 수리구조물의 형식과 다양한 운영방식에 따른 수리학적 분석내용이 적절하게 반영되지 않은 경험공식이 대부분 적용되었다. 따라서 예상보다 매우 큰 하상유실이 발생 하여, 하상보호구조물의 설치역할을 제대로 수행하지 못하고 오히려 수리구조물의 안정성에 위협을 주는 주요한 요인이 되었다. 그리고 최근 국내에는 4 대강 유역에 16개 중 대규모의 다목적 보가 설치되었으나 앞서 언급한 바와 같이 미흡한 설계지침을 기반으로 설치된 보 및 하상보호구조물의 기능이 저하되어 극심한 세굴현상이 발생하였다. 또한 이를 보강하기 위한 추가적인 공사 등으로 경제적인 손실을 야기하였다. 반면 외국의 최근 설계지침에는 하상보호구조물 하류부에서 발생하는 평형최대세굴심의 규모를 고려하거나 흐름 및 난류분포를 고려한 수리학적 분석이 반영되어 있지만 국내 설계지침에는 전무한 실정이다. 따라서 본 연구에서는 기존 국내 설계지침의 한계를 조사하고 현재 외국에서 적절하게 제안되어 적용 중인 하상보호구조물 설계지침을 검토하였다. 특히 수리학적 거동특성과 유사분포 특성이 고려된 최대세굴심 산정공식과 설계지침을 검토하였고, 평형상태에 도달한 세굴공 내에서의 수리학적 특성을 고려하여 하상보호구조물의 길이를 적절히 산정할 수 있는 기존 연구결과를 토대로, 하상보호구조물 길이 산정공식을 제안하였다. 본 연구에서 검토된 외국 설계지침과 함께 수리학적 거동특성이 고려된 하상보호구조물의 길이 산정공식은, 향후 수리구조물의 안정성 확보를 위한 하상보호구조물의 설계에 반영될 필요가 있으며, 이를 통해 수리구조물의 효율적이고 경제적인 유지관리를 위해 적절히 활용될 수 있다.

• The Transactions of the Korea Information Processing Society
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• v.13 no.2
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• pp.1-12
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• 2024

Modern cities are actively adopting smart city services to address various urban challenges. Geospatial information acts as the foundational infrastructure of smart cities, promoting the sustainable development of urban areas. Consequently, as the standardization and utilization of geospatial information increase, the efficiency and sustainability of smart city operations improve. To achieve this, collaboration among diverse stakeholders is crucial for delivering optimal smart city services based on geospatial information. This paper defines smart city services, focusing on transportation and building-energy domains, based on the life cycle of geospatial information technology. Emphasis is placed on the importance of applying and utilizing geospatial information standards. Additionally, this paper proposes the Smart City based on Geospatial Information standards (SCGI) framework to provide insights into standardizing smart city services mapped to geospatial information standards. This research suggests a new paradigm for standardizing smart city services using geospatial information standards to offer customized solutions, thereby discussing the future development possibilities of smart cities.

• Journal of Korea Port Economic Association
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• v.38 no.4
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• pp.65-85
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• 2022

In this study, in order to derive the priority of indicators and sustainability areas of smart ports, which means ports in the digital era, previous studies and ESG, which have recently been indispensably introduced in all industries worldwide, were studied together. A hierarchical structure was established with upper evaluation items and 20 lower evaluation items in four areas (operational, environmental, social, and governance), and a relative evaluation method of weighting items among the AHP techniques was applied. The pairwise comparison questionnaire consisted of a 9-point scale proposed by Satty (1980). A survey was conducted targeting working-level workers who perform sustainability or ESG(Environmental, Social, Governance)-related work at four representative port authorities in Korea (Busan, Incheon, Ulsan, Yeosu Gwangyang). In order to increase the accuracy of the analysis results, AHP analysis was conducted on 17 questionnaires with a consistency ratio of 0.1 or less. As a result of the analysis, it was confirmed that among the four areas representing the sustainability of domestic smart ports, the operation area had the highest priority, followed by the environment area. In addition, looking at the overall priorities for the 20 detailed indicators, indicators such as operational efficiency, operational planning, energy management, and pollution measurement and management system were found to have high priority. On the other hand, it was confirmed that the social and the governance areas had relatively low importance compared to other areas.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.31-43
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• 2015

For battery based real-time embedded systems, high performance to meet their real-time constraints and energy efficiency to extend battery life are both essential. Real-Time Dynamic Voltage Scaling (RT-DVS) has been a key technique to satisfy both requirements. In this paper, we present an efficient RT-DVS algorithm called EccEDF that is designed based on ccEDF. The proposed algorithm can precisely calculate the maximum unused utilization with consideration of the elapsed time while keeping the structural simplicity of ccEDF, which overlooked the time needed to run the task in calculating the available slack. The maximum unused utilization can be calculated by dividing remaining execution time($C_i-cc_i$) by remaining time($P_i-E_i$) on completion of the task and it is proved using Fluid scheduling model. We also show that the algorithm outperforms ccEDF in practical applications which is modelled using a PXA250 and a 0.28V-to-1.2V wide-operating-range IA-32 processor model.

• Journal of IKEEE
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• v.22 no.2
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• pp.324-329
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• 2018

As the environment of power systems changes, the demand and necessity for new electrical energy market are increasing. Especially, efforts to increase the efficiency of electric energy use by using demand response programs are being studied constantly in advanced countries and it is operated as a real market. This paper presents a study on the baseline load estimation required in the new power market, such as demand response, P2P electricity trading etc. The proposed method estimates the baeline load through analysis of the load pattern and verifies the effectiveness of the proposed method using actual data.