• The KIPS Transactions:PartC
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• v.15C no.5
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• pp.383-390
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• 2008

The mobile sink is most suitable to guarantee the real time processing to events in ubiquitous environment. However it brings many challenges to wireless sensor networks. In particular, the question of how to transfer the collected data to the mobile sink is an important topic in the aspect of effective management of wireless sensor nodes. In this paper, a new data dissemination model is proposed. Since this method uses the home agent and the access node concepts, it provides reliable and efficient data delivery to mobile sink with minimum overhead. In this proposed method, the information of the mobile sink which is constantly moving is informed only to the home agent node and the access node, instead of all sensor nodes. Thus, the collected data from sensor nodes are transferred to the fixed home agent and it sends these data to the mobile sink. Since the confliction phenomenon between data packets in wireless networks could be reduced, the success ratio of data arriving in the mobile sink is highly enhanced. In our experiments, the proposed method reduces the number of broadcast packets so that it saves the amount of energy consumed for transmitting and receiving the data packets. This effect contributes to prolong the lifetime of the wireless sensor networks operated by batteries.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.969-972
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• 2015

Many studies have been carried out in order to develop a frequency efficient communication system than the current communication system for satisfying the increasing demands of wireless data services in mobile communication systems. If a communication system dramatically improving the frequency utilization efficiency is not developed, service providers must maintain more number of base station equipments to meet the increasing demands of wireless data service. Service provider needs a system or method to reduce maintenance costs. Demands of wireless data service are changed according to time of day, location and so on. Power consumption can be reduced if the supplied power of communication systems is controlled by wireless data traffics. This paper describes the design and implementation of power management system of mobile communication base station's equipment based on smart grid. The proposed power management system controls the supplied power to the mobile communication infrastructures depending on the demand of wireless data. Field test results of the implemented system show the proposed system saves 26% of the power consumption in the base stations.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.7
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• pp.199-204
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• 2021

Digital substation refers to a substation that digitizes functions and communication methods of power facilities such as monitoring, measuring, control, protection, and operation based on IEC 61850, an international standard for the purpose of intelligent power grids. Based on the intelligent operating system, efficient monitoring and control of power facilities is possible, and automatic recovery function and remote control are possible in the event of an accident, enabling rapid power failure recovery. With the development of digital technology and the expansion of the introduction of eco-friendly renewable energy and electric vehicles, the spread of direct current distribution systems is expected to expand. MVDC is a system that utilizes direct current lines with voltage levels and transmission capacities between HVDCs applied to conventional transmission systems and LVDCs from consumers. Converting existing lines in substations, where most power equipment is alternating current centric, to direct current lines will reduce transmission losses and ensure greater current capacity. The process bus of a digital substation is a communication network consisting of communication equipment such as Ethernet switches that connect installed devices between bay level and process level. For MVDC linkage to existing digital substations, the process level was divided into two buses: AC and DC, and a system that can be comprehensively managed in conjunction with diagnostic IEDs as well as surveillance and control was proposed.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.161-171
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• 2019

Varied methods have been researched continuously because the past as the daily maximum electricity demand expectation has been a crucial task in the nation's electrical supply and demand. Forecasting the daily peak electricity demand accurately can prepare the daily operating program about the generating unit, and contribute the reduction of the consumption of the unnecessary energy source through efficient operating facilities. This method also has the advantage that can prepare anticipatively in the reserve margin reduced problem due to the power consumption superabundant by heating and air conditioning that can estimate the daily peak load. This paper researched a model that can forecast the next day's daily peak load when considering the influence of temperature and weekday, weekend, and holidays in the Seasonal ARIMA, TBATS, Seasonal Reg-ARIMA, and NNETAR model. The results of the forecasting performance test on the model of this paper for a Seasonal Reg-ARIMA model and NNETAR model that can consider the day of the week, and temperature showed better forecasting performance than a model that cannot consider these factors. The forecasting performance of the NNETAR model that utilized the artificial neural network was most outstanding.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.344-350
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• 2003

In this paper, we propose a novel sharing method ordering the events occurring between users collaborated with the common telecomputing environment. We realize the sharing method with multimedia data to improve the coworking effect using teleprocessing network. This sharing method advances the efficiency of communicating projects such as remote education, tele-conference, and co-authoring of multimedia contents by offering conveniences of presentation, group authoring, common management, and transient event productions of the users. As for the conventional sharing white board system, all the multimedia contents segments should be authored by the exclusive program, and we cannot use any existing contents or program. Moreover we suffer from the problem that ordering error occurs in the teleprocessing operation because we do not have any line-up technology for the input ordering of commands. Therefore we develop a method of retrieving input and output events from the windows system and the message hooking technology which transmits between programs in the operating system In addition, we realize the allocation technology of the processing results for all sharing users of the distributed computing environment without any error. Our sharing technology should contribute to improve the face-to-face coworking efficiency for multimedia contents authoring, common blackboard system in the area of remote educations, and presentation display in visual conference.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.345-353
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• 2022

A wastewater treatment plant (WWTP) is a major gateway for the engineered nano-particles (ENPs) entering the water bodies. However existing studies have reported that many WWTPs exceed the No Observed Effective Concentration (NOEC) for ENPs in the effluent and thus they need to be designed or operated to more effectively control ENPs. Understanding and predicting ENPs behaviors in the unit and \the whole process of a WWTP should be the key first step to develop strategies for controlling ENPs using a WWTP. This study aims to provide a modeling tool for predicting behaviors and removal efficiencies of ENPs in a WWTP associated with process characteristics and major operating conditions. In the developed model, four unit processes for water treatment (primary clarifier, bioreactor, secondary clarifier, and tertiary treatment unit) were considered. Additionally the model simulates the sludge treatment system as a single process that integrates multiple unit processes including thickeners, digesters, and dewatering units. The simulated ENP was nano-sized TiO₂, (nano-TiO₂) assuming that its behavior in a WWTP is dominated by the attachment with suspendid solids (SS), while dissolution and transformation are insignificant. The attachment mechanism of nano-TiO₂ to SS was incorporated into the model equations using the apparent solid-liquid partition coefficient (Kd) under the equilibrium assumption between solid and liquid phase, and a steady state condition of nano-TiO₂ was assumed. Furthermore, an MS Excel-based user interface was developed to provide user-friendly environment for the nano-TiO₂ removal efficiency calculations. Using the developed model, a preliminary simulation was conducted to examine how the solid retention time (SRT), a major operating variable affects the removal efficiency of nano-TiO₂ particles in a WWTP.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2005.09a
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• pp.45-72
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• 2005

쌀을 주식으로 하는 우리의 식생활과 일치하고 전통적으로 나누어 함께 먹는 식품으로 자리 잡고 있는 떡을 현대화하기 위해서는 인식의 전환과 상품화 및 유통기간연장을 위한 연구가 이루어 져야한다. 영양학적으로 우수한 전통 떡류가 있지만 현대에 이르러서 생활양식과 식문화 등의 급격한 변화로 일반화 및 다소비 되지 못함은 소비자의 변화에 맞추지 못하기 때문이나 떡에 대한 인식은 매우 긍정적이라고 한다. 떡은 언제 어디서나 먹을 수 있는 간편한 생활 음식이며, 우수한 전통음식이라고 인식시킴으로써 떡에 대한 긍정적인 이미지를 확대해 나갈 필요가 있다. 전통의 맛을 유지하면서 기능성과 영양상의 균형을 갖춘 새로운 맛의 떡으로 소비층을 확대하여야 한다. 유통기간이 짧아 떡집에 자주 가서 구매해야 한다는 인식에 탈피 할 수 있도록 제품개발이 되어야 한다. 떡집은 영세하고, 비위생적이며 포장이 깨끗하지 못하다는 인식이 전환이 되도록 작업환경, 시설 및 제품포장을 현대화 하여야 한다. 새로운 형태의 매장을 운영하는 것도 필요하다. 새로운 형태의 카페 형 또는 베이커리형의 떡집이 선보임으로써 다양한 종류의 떡이 개발되어 편의성과 고급화되면 소비층이 점차 확대되고 있는 점은 떡의 상품화와 관련하여 매우 의미 있는 변화이다. 또한 떡 공장에서 위생적으로 생산, 소규모 포장, 급속 동결, 냉동 유통, 소비자에게 전달되는 냉동제품이 활성화 되어야 한다. 노화억제에 의한 저장성 향상은 상품화 떡의 품질향상이다. 품질과 관련된 인자는 원료 쌀의 품질, 분쇄 정도, 수분함량, 제조공정, 전분분해 효소처리, 당류, 유화제, 콜로이드 물질 등의 첨가제에 의한 연구가 지속되고 있다.학적 특성에는 영향을 미치지 않고 혈중 IGF-I 농도를 증가시켰다. 또한 이들 측정항목에서 Revalor H implant는 제한사양, 저에너지 사료, 혹은 Compudose 이상의 효과를 나타내었고, 증체를 억제하였으나 사료효율은 증진시켰으며, 후자(사양, 사료)와의 상호작용은 나타나지 않았다. 이상의 결과는 거세비육돈에서 1) androgen과 estrogen은 공히 자발적인 사료섭취와 등지방 침적을 억제하고 IGF-I 분비를 증가시키며, 2) 성선스테로이드호르몬의 이 같은 성장에 미치는 효과의 일부는 IGF-I을 통해 매개될 수도 있을을 시사한다. 약 $70 {\~} 90\%$의 phenoxyethanol이 유상에 존재하였다. 또한, 미생물에 대한 항균력도 phenoxyethanol이 수상에 많이 존재할수록 증가하는 경향을 나타내었다. 따라서, 제형 내 oil tomposition을 변화시킴으로써 phenoxyethanol의 사용량을 줄일 수 있을 뿐만 아니라, 피부 투과를 감소시켜 보다 피부 자극이 적은 저자극 방부시스템 개발이 가능하리라 보여 진다. 첨가하여 제조한 curd yoghurt는 저장성과 관능적인 면에서 우수한 상품적 가치가 인정되는 새로운 기능성 신제품의 개발에 기여할 수 있을 것으로 사료되었다. 여자의 경우 0.8이상이 되어서 심혈관계 질환의 위험 범위에 속하는 수준이었다. 삼두근의 두겹 두께는 남녀 각각 $20.2\pm8.58cm,\;22.2\pm4.40mm$으로 남녀간에 유의한 차이는 없었다. 조사대상자의 식습관 상태는 전체 대상자의 $84.4\%$가 대부분이 하루 세끼

• Journal of Convergence for Information Technology
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• v.11 no.9
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• pp.94-108
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• 2021

This study is to identify the internal and external factors of a company that can affect the rate of change in the inventory turnover ratio. In addition, by appropriately managing or responding to these factors, changes in the inventory turnover ratio do not occur abruptly, so that the company's business and financial performance can be improved. To confirm this, factors such as gross profit margin, cash flow volatility, advertising expenses, inflation, exchange rate rise, and leading economic index were selected, and these factors were predicted to affect the change rate of inventory turnover. Data of 85,878 companies were obtained from domestic securities listings, KOSDAQ listings, and externally audited companies, and multiple regression analysis was performed using the data. Gross profit margin and cash flow volatility have a significant positive (+) effect, advertising expenses have a negative (-) significant effect, and inflation and exchange rate rises have a negative (-) significant effect. As an influence, the leading economic index was tested to have a significant positive (+) effect. Through this, it is suggested that manufacturing companies can improve their business performance and achieve operational efficiency by well understanding and appropriately managing factors that can affect the change rate of inventory turnover.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.73-84
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• 2021

Recently, interest in environmental issues is increasing worldwide due to abnormal climate phenomena caused by global warming. Global efforts are continuing to actively respond to climate change, but the dependence on fossil fuels is still high. In particular, a huge amount of fossil fuels and mineral resources are buried in the Arctic Circle, so development and construction projects are being actively pursued. Participation and cooperation in the development of Arctic resources (oil and gas resources) is one of the alternatives to domestic energy supply. Resource development in the Arctic Circle requires close review(Poor development environment and technical limitations due to extreme climate, environmental problems due to resource development, social impact, etc.) in advance compared to general resource development. In this pater, the laws and guidelines related to climate change to be considered were reviewed. when developing Arctic resources. In addition, the countermeasures against climate change applied in large-scale resource development projects in the Arctic were reviewed. It is expected that the results of the research and analysis of this study will be used to establish strategies to respond to new risk factors that influence the successful promotion and operation of the Arctic region resource development project.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.46-46
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• 2021

국제사회는 1992년 기후변화협약 체결 이후 지구온도 상승을 2℃이하로 억제하는 등 기후변화 문제를 해결하기 위해 노력하고 있다. 그러나 1997년 선진국(38개국) 중심으로 2020년까지 탄소감축(교토의정서)을 선언하였음에도 불구하고, 미국, 중국 등의 감축의무 미참여로 인해 기후변화대응에 대한 한계를 노출한 바 있다. 그 이후 COP21(2015년)에서 모든 국가에 감축의무를 부여하는 신(新)기후체제를 출범함으로써 선진국뿐만 아니라 개발도상국도 2020년부터 탄소감축의무를 부담하게 되었다. 영국은 기후변화위원회의 권고에 따라 탄소중립경제(Net-Zero Economy) 실현을 위해 국가적 탄소배출 목표를 발표(2019년)하고 온실가스 배출 'Zero'를 기후변화법에 명시하여 모든 산업 인프라 및 환경에 적용시키려 한다. 전 세계에서 최초로 영국의 물산업 분야는 'Net Zero 2030 Routemap'을 발표하여 물산업분야의 탄소중립 실현을 위해 다양한 정책적 로드맵과 실행방안(시나리오)을 수립하였다. 이러한 실행방안은 국가정책에 부합하고 자국내 물기업의 탄소저감 실행계획의 수립을 지원하는데 그 목적이 있다. 구체적인 실행방안은 탄소중립 달성을 위해 비용, 효과, 기술수준 및 기간 등을 고려하여, ①수요주도형, ②기술주도형, ③자연친화주도형, 그리고 ④복합형으로 제시하고 있다. 실행시나리오에 따르면, 수요주도형은 상하수도 분야 수요관리 및 기술, 설비의 효율화를 통한 배출 저감 방안으로 2018~19년 기준, 총배출량 2.41MtCO2e에서 2030년까지 0.54MtCO2e으로 약 77%의 감소효과를 기대하고 있다. 기술주도형의 경우, 심각한 탄소배출 분야의 기술개발 및 혁신을 통해 배출량을 최소화하는 시나리오이며, 총배출량(2.41MtCO2e)을 0.10MtCO2e(약 96%)까지 감소시키기 위한 방안이다. 자연친화주도형은 물기업의 자산 및 그 외 지역에 자연친화적 환경조성을 통한 탄소상쇄방안을 중심으로 총배출량을 0.88MtCO2e(약 63%)까지 저감하는 효과를 나타낸다. 마지막으로 복합협은 시나리오별 실효성과 적용시기를 고려할 때 가장 효과적인 방안으로 약 74%의 저감효과를 나타내지만, 시기적절성, 효과성에서, 가장 최적의 방안으로 제시되고 있다. 본 연구는 이러한 영국 물산업 분야의 탄소중립 정책과 실행방안 분석하고 그 시사점을 제시함으로써 국내 물산업 분야의 탄소중립을 위한 구체적 실행계획 수립에 이바지하고자 한다. 물산업 분야의 탄소중립은 기존 물산업 가치사슬 변화 등 물산업 생태계 전반의 변화를 초래할 것이며, 이러한 변화는 국내 물산업의 자본·운영시장의 비용증가에 대한 도전과 신재생에너지 기술 등 탄소 중립 기술 습득 및 새로운 일자리 창출 등 신(新)시장체계에 대한 기회가 동시에 상존한다.