• Korean Journal of Construction Engineering and Management
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• v.22 no.2
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• pp.53-62
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• 2021

PC component allocation and loading plan can contribute to reductions in carbon dioxide emission and energy use of vehicles and total project costs with increased utilization of vehicle loading space. The study derived 18 considerations that PC construction plant managers and site managers take into account when they plan allocation and loading of PC components. Then, IPA (Importance and Performance Analysis) was performed to assess importance and performance of the 18 considerations. Results show that in the PC component allocation planning, considerations regarding the number of vehicles and existence of yard for storing PC components have not been taken into account well by the managers. In the PC component loading planning, PC component loading direction has not been reflected well by the managers although it is considered important by them. Recently, ill-planning issues of PC component transportation, such as inefficient use of vehicle space and loading with low stability, are frequent due to various types of PC components produced. In this context, if the results of this study are reflected in the development of component allocation and loading planning, vehicle management of PC projects would be more efficient, thereby leading to economic project management.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5B
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• pp.327-337
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• 2012

There have been lots of researches on the optimal relay selection in relay-based systems. However, most researches have been focused on the maximization of transmission capacity with a constraint of sum power at both transmitter and relays. In Ad-hoc networks where relays have batteries of limited power, it is imperative to minimize the energy consumption while maintaining the required quality-of-service (QoS). In this paper, we propose an optimal relay selection strategy to minimize the relay power consumption while satisfying the required signal-to-noise ratio (SNR). Through intensive simulations, we show the proposed method is more effective in terms of energy consumption and guarantee lower transmission failure probability in multi-hop Ad-hoc environments.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.4
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• pp.159-167
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• 2018

In this paper, we propose an algorithm to optimize energy efficiency in a multi-user decoupled RF energy harvesting network and experiment on the trend of energy efficiency change assuming users' various geographical distribution scenarios. In the RF energy harvesting network where both wireless data transmission and RF energy harvesting are simultaneously performed, the energy efficiency is a key indicator of network performance, and it is necessary to investigate how various factors can affect the energy efficiency. In order to increase energy efficiency effectively, we can confirm that users' distributions are important factors in the RF energy harvesting network from the simulation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.623-625
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• 2015

Recently, the cooling water of power plant was included in RPS(Renewable Portpolio Standard) as water heat energy. Thus the trend of cooling water application is growing bigger for agriculture and fishing industry. Especially as energy consumption cost in agriculture and fishing industry is a vital element, the interests for energy efficiency is growing bigger. The advanced agriculture country like Netherlands is distributing diagnosis software to the farmers based on ICT diagnostic system for the efficient energy consumption and energy demand amounts depend on crops of cultivation in automated horticulture. Hereafter, in the preparation of the expansion of the automated agriculture domestically by the cooling water of power plant, we would like to propose the energy application case(Greenery) in the advanced countries abroad in agriculture and EMS system about the application of the cooling water in power plant.

• Bulletin of Korea Environmental Preservation Association
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• s.413
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• pp.14-17
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• 2014

배출권거래제가 내년 1월부터 시행될 예정이다. 이에 기업들은 실제 온실가스 배출증가 추세와 신 증설 시설 투자계획 등을 고려한 현실적인 할당이 이루어지길 원하며 정부는 국가 감축목표 달성이 가능하도록 할당량을 결정하고자 한다. 온실가스 감축목표는 다양한 정책의 종합결과물로서 에너지정책, 산업발전정책, 온실가스 감촉기술발전 추이 등이 종합적으로 고려되어야 한다. 배출권거래제의 안정적 운영과 지속적인 경제성장을 담보하기 위해서라도 환경보전과 산업경쟁력을 동시에 고려하는 합리적 대안이 마련되기를 희망해 본다.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.9
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• pp.1333-1342
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• 2013

New & renewable energy becomes a crucial subject to solve the problems inherent in the current energy resources, which results in the fast development of the new & renewable energy industry worldwide. However, not only its base is still weak but the high initial investment for technology development and certain scale of an energy market are required in many cases. For this reason, many countries in the world, including Korea, run the energy policies to foster the new & renewable energy industry such as RSP and FIT. In general, a policy should be established to take various, intertwined interests as well as a number of variables related to economic, social, environmental, and international matters into comprehensive consideration. For new & renewable energy industry, there are many variables to be considered and indexes necessary for evaluation but it is hard to take all of them into account. Even though they were considered, no criteria are available for use in a consistent manner. Therefore, this study plans to develop an evaluation model for the Korean new & renewable energy policy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1549-1555
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• 2009

The Relay node placement problem is one of the most important requirements for many wireless sensor networks because the lifetime of sensor networks is closely related with the placement of relay nodes which receive sensed data from sensor nodes and forward them to the base station. Relay node placement problem has focused at minimization of dissipated total energy of the sensor nodes in whole networks. However, minimum total energy causes the unbalance of consumed energy in sensor nodes due to different distances between relay nodes and sensor nodes. This paper proposes the concept of energy balance ratio and finds the locations of relay nodes using objective functions which maximize the energy balance ratio. Maximizing this ratio results in maximizing the network lifetime by minimizing the energy consumption of large-scale sensor networks. However, finding a solution to relay node placement problem is NP-hard and it is very difficult to get exact solutions. Therefore, we get approximate solutions to EBR-RNP problem which considers both energy balance ratio and relay node placement using constraint programming.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.6
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• pp.3-9
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• 2015

We investigate rate scheduling and power allocation problem for a delay constrained CDMA systems. Specifically, we determine an energy efficient scheduling policy, while each user maintains the short term (n time slots) average throughput. We consider a multirate CDMA system where multirate is achieved by multiple codes. Each code can be interpreted as a virtual user. The aim is to schedule the virtual users into each time slot, such that the sum of transmit energy in n time slots is minimized. We then show that the total energy minimization problem can be solved by a shortest path algorithm. We compare the performance of the optimum scheduling with that of TDMA-type scheduling.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.360-370
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• 2009

Using solar power in wireless sensor networks requires a different approach to energy optimization from networks with battery-based nodes. Solar energy is an inexhaustible supply which can potentially allow a system to run forever, but there are several issues to be considered such as the uncertainty of energy supply and the constraint of rechargeable battery capacity. In this paper, we present SolarSS: a reliable storage system for solar-powered sensor networks, which provides a set of functions, in separate layers, such as sensory data collection, replication to prevent failure-induced data loss, and storage balancing to prevent depletion-induced data loss. SolarSS adapts the level of layers activated dynamically depending on solar energy availability, and provides an efficient resource allocation and data distribution scheme to minimize data loss.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.712-713
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• 2011

2012년부터 시행 예정인 신재생에너지 의무할당제(RPS)의 도입으로 향후 태양광 및 풍력 등의 그린 에너지가 향후 지속적으로 배전계통에 연계, 운용될 것으로 예상된다. 이때 정상상태의 계통전압을 해석하기 위해서는 부하모델링이 필수적이다. 본 논문에서는 가장 많이 활용되고 있는 ZIP 부하모델을 활용하여 배전계통에서 효과적인 전압해석법을 제안하고, 수치해석 및 PSCAD/EMTDC를 이용하여 제안한 전압해석법의 유효성을 검증한다.