• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2641-2646
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• 2009

The more growing on home automation system at automatic control, the more efficiency required for energy consumption and for recycling energy in near future. Heating is essential in general apartment. Heating method is two types in apartment. One uses electricity, and other one uses warm water. If use electricity, is not efficient by rise of electric charges. But, It can reduce much in expense aspect, if use warm water. When use warm water, temperature of warm water is not equal from all pipe parts. Therefore, indoor tempera can be unequal with set point. Solution of these problems is as following. Temperature sensor in warm water attach pipe. The measured temperature transmits by real time. Temperature of warm water controls in receiver side. In this paper, we propose an automatic temperature transmission system for the heating pipe at home, that is a low-power based, and supply the energy source from a small AC motor resided in bottom cement mortal. The proposed system is used in power mechanism from a collision process of water-jet using propeller water-difference and also designed a CPU module by Atmega8 at ATMEL co., Inc. and a communication module by CC1020 at Chipcon co., Inc.

• Journal of Environmental Impact Assessment
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• v.28 no.6
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• pp.556-567
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• 2019

As the number of skyscrapers in micro water grid units such as green building and smart building is increasing in the world, the green building certification system is being implemented to solve problems such as increased demand for water resources and energy. However, researches on the use of sustainable water resources like water reuse and water conservation through linkage and continuous use of water resources, while the power and energy sectors are actively conducting R&D projects in the green building certification system on the micro water grid level. Therefore, this paper analyzes the characteristics and limitations of the water resources sector for the continuous utilization of multiple water sources in the green building certification system, due to the inadequate consideration of sustainability. Then investigates whether various water resources such as constants, nature, and alternative water resources are continuously used in and out of the green building or smart building and complex in the micro water grid unit to suggest evaluation methods and performance evaluation standards.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.439-439
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• 2012

본 연구의 목적은 색달하수처리장 방류수를 농업용수 및 조경용수 등으로 활용하기 위해 하수 처리수 재이용 사업 타당성을 분석하고자 한다. 색달하수처리장 하수재이용사업은 제주도의 지하수자원 보존과 수자원 이용의 고도화 및 방류수 재이용을 통한 갈수기 농업용수 보급으로 물자원(지하수)을 절약하고자 색달하수처리장을 대상으로 하수처리수를 농업용수로 공급하는 사업이다. 대상지역은 서귀포시 예래동에 위치하고 있으며, 중문관광단지가 소재한 마을로 제주관광의 중심지이다. 서귀포시의 총 인구는 153,797명이며 하수도 보급률은 77.7%이다('10 제주특별자치도 통계연보). 색달하수처리장이 위치한 예래동의 농지면적이 1,122ha이며, 밭(772.6)과 과수원(280.2) 등 제주도의 전형적인 농촌마을이다. 대상지역의 주요작물은 감귤, 무, 마늘, 양배추 등이 많이 재배된다. 제주도는 연평균 강수량이 1,832.6mm로 전국평균 1,274 mm 보다 많은 편이며, 월별 강수량은 6~8월까지 3개월 동안 연 강우량의 44%정도가 내려 여름 장마철에 집중되는 것으로 나타났다. 대상지구의 필요수량은 농업생산정비 계획설계기준에 제시된 방법을 이용하여 산정하였다. 지구내 재이용수를 공급할 관정 4개소의 총 설계 채수량은 $2,916m^3/day$, 급수면적은 125.0ha이며, 10년한발(가뭄)시 안정적인 농업용수 공급을 위하여 $4,964m^3/day$(농업용수 $3,834m^3/day$, 조경용수 $1,130m^3/day$)이 필요하다. 하수처리수 재이용을 위한 처리시설의 연간 유지관리비는 인건비, 전력비, 시설물 내구연한을 고려하여 적용 하였으며, 상수도 생산비 절감 비용과 하수재이용수 생산단가를 통한 단위 편익을 산정하면 401.5원/$m^3$ 이다. 연차별 수익으로 산정하여 비용 편익 비율(B/C Ratio)을 나타내면 1.22로 나타났다. 본 연구의 결과로부터, 대상지구의 수자원여건, 입지여건, 장래 수요, 등을 고려할 때, 제주 색달 하수처리장의 하수처리수의 농업용수재이용 사업은 타당성이 매우 높다고 할 수 있다. 그리고 특히 이 지역은 관광단지의 조경용수 수요(중문골프장 등)가 있어 용수의 유료공급이 가능하고 이를 유지관리비로 충당할 수 있어 타지역에 비해 사업의 경제성과 환경보전성이 매우 크다.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.783-798
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• 2004

An e-business client application in ubiquitous mobile computing environment may become disconnected from the enterprise server due to broken communication connections caused by the limitation of mobile computing environments(limited battery life of the mobile device, low bandwidth communication, incomplete wireless communication infrastructure, etc). It Is even Possible that mobile client application Intentionally operates in disconnected mode to reduce communication cost and the power consumption of the mobile device. We use “data hoarding” as a means of providing local autonomy to allow transactions to be processed and committed on the mobile host despite of disconnection. The key problem to this approach is the synchronization problem that serialize potentially conflicting updates from disconnected clients on master objects of the server database. In this paper, we present a new transaction synchronizing method that splits a transaction into a set of independent component transactions and give the synchronization priority on each component taking the possibility of use and conflicts in the server into consideration. Synchronization is performed component by component based un synchronization priority. After the Preferred component of a no bile transaction succeeds in synchronization with the server, the mobile transaction can pre-commit at server. A pre-committed transaction's updated value is made visible at server before the final commit of the transaction. The synchronization of the component with low synchronization priority can be delayed in adaption to wireless bandwidth and computing resources. As a result, the availability of important data updated by mobile client is increased and it can maximize the utilization of the limited wireless bandwidth and computing resources.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.498-498
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• 2022

통합물관리를 위한 농촌용수 이 치수 관련 거버넌스를 체계화하고 기반을 마련하고자 지역 내 거버넌스 및 통합물관리에 대한 사례조사, 의견 수렴, 토론 및 소통 등의 과정을 거쳐 사회적으로 수용성이 높은 '농촌용수 통합물관리 거버넌스의 운영 방안' 모델 개발을 중심으로 수행하였다. 우리나라의 물관련 거버넌스는 해당 유역과 단체의 물문제를 중심으로 활동하고 있으며, 국가적 차원의 통합물관리 체계에 발맞춰 나가기 위해서는 농업인 거버넌스 활성화가 필요하다. 또한 농업인 거버넌스는 농업용수 등 물관련 문제 해결에 적극 참여하여 협력과 소통을 기반으로 농업용수부문의 주도권을 확보하여야 할 것이다. 지역 물관리 현황 분석 및 현안 과제를 도출하기 위해 최근 농업용수와 관련한 민감한 이슈가 있는 금강유역 내 위치한 지구를 시범지구로 선정하였다. 논 시범지구는 현북 양수장으로 선정하였으며, 비교지구는 정암 양수장으로 선정하였다. 시범지구인 현북 양수장은 충남 부여군에 위치하고 있어 농업인 단체의 지역본부나 지회가 참여 할 수 있도록 하였다. 또한 통합물관리를 위한 현장의 주체인 수감원과 시설관리기관인 한국농어촌공사 부여지사가 참여하도록 하였다. 농촌용수 통합물관리 거버넌스는 협의의 거버넌스와 광의의 거버넌스로 구분하였다. 협의의 거버넌스 구성은 해당지구의 농업인, 기초지방자치단체, 한국농어촌공사 지사 등으로 구성한다. 광의의 거버넌스 구성은 해당지구의 광역 및 기초지방자치단체, 한국농어촌공사 지사, 지역의 농업인 사회단체 등 10개 이내의 기관과 단체로 구성한다. 거버넌스의 주된 활동은 해당 지역·지구의 농업용수 관리 개선 및 농업인의 적극적 참여를 위한 광역지방자치단체, 기초지방자치단체 및 한국농어촌공사와의 소통과 협력, 갈등을 조정한다. 이와 더불어 농업용수관리 개선을 위한 정책개발, 기존 제도의 개선, 효율적인 물관리를 위한 실천사업 관련된 다양한 연구조사사업 수행, 지역 농업인 영농 활동의 질 향상을 위한 욕구 조사, 중복규제 등 현안 사안에 대한 법 및 정책 개선, 대안 발굴 등 정책과 제도운영 및 개선방안 연구·조사 사업에 전력투구하는 조직체로서 기능을 수행한다. 따라서, 농업인들이 자발적으로 국가적 차원에서 제시하는 농업용수 관련 정책을 따르기 위해 농촌용수 통합물관리 거버넌스를 통한 정책 제안이 반드시 필요하다.

• Journal of the Korea Concrete Institute
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• v.19 no.1
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• pp.121-130
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• 2007

To investigate the enhancement in strength and deformation capacities of concrete confined by FRP composites, tests under axial loads were carried out on three groups of thirty six short columns in circular section with diverse GFRP confining reinforcement. The major test variables considered include fiber content or orientation, wrap or tube type by varying the end loading condition, and continuous or discontinuous confinement depending on the presence of vortical spices between its two halves. The circumferential FRP strains at failure for different types of confinements were also investigated with emphasis. Various analytical models capable of predicting the ultimate strength and strain of the confined concrete were examined by comparing to observed results. Tests results showed that FRP wraps or tubes provide the substantial increase in strength and deformation, while partial wraps comprising the vertical discontinuities fail in an explosive manner with less increase in strength, particularly in deformation. A bilinear stress-strain response was observed throughout all tests with some variations of strain hardening. The failure hoop strains measured on the FRP surface were less than those obtained from the tensile coupons in all tests with a high degree of variation. In overall, existing predictive equations overestimated ultimate strengths and strains observed in present tests, with a much larger scatter related to the latter. For more accuracy, two simple design- oriented equations correlated with present tests are proposed. The strength equation was derived using the Mohr-Coulomb failure criterion, whereas the strain equation was based on entirely fitting of test data including the unconfined concrete strength as one of governing factors.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.503-515
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• 2014

A lot of existing wastewater treatment plants (WWTPs) are rebuilt or retrofitted for advanced wastewater treatment processes to cope with reinforced effluent criteria of nitrogen and phosphorous. Moreover, how to treat the wasted sludge from WWTPs has been also issued since the discharge of the wasted sludge into ocean is impossible from 2011 due to the London Convention 97 protocol. These trend changes of WWTPs get a motivation to assess environmental and economic impacts from the construction stage to the waste stage in WWTPs. Therefore, this study focuses on evaluation of environmental and economic impacts of the advanced wastewater treatment processes and waste sludge treatment process by using life cycle assessment. Four advanced wastewater treatment processes of Anaerobic/Anoxic/Oxic ($A_2O$), 5 stages-Bamard Denitrification Phosphate (Bardenpho), Virginia Initiative Plant (VIP), and Modified University of Cape Town (MUCT) are chosen to compare the conventional activated sludge (CAS) and three waste sludge treatment methods of land fill, incineration, and composting are used. To evaluate environmental and economic impacts of each advanced wastewater treatment processes, life cycle assessment (LCA) and life cycle cost (LCC) are conducted based on International organization for standardization (ISO) guidelines. The results clearly represent that the $A_2O$ process with composting shows 52% reduction in the environmental impact than the CAS process with landfill. On the other hand, the MUCT process with composting is able to save 62% of the life cycle cost comparing with the CAS process with landfill. This result suggested the qualitative and quantitative criteria for evaluating eco-environmental and economic technologies of advanced treatment processes and also sludge treatment method, where their main influence factors on environmental and economic impacts are analyzed, respectively. The proposed method could be useful for selecting the most efficient and eco-friendly wastewater treatment process and sludge treatment method when retrofitting the existing WWTPs to advanced treatments.

• Environmental and Resource Economics Review
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• v.14 no.2
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• pp.257-290
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• 2005

Korean energy use in industrial sector has increased more rapidly than other sectors during 1980~2000 periods. Relatively higher increases in industrial sector energy consumption raise questions whether government policy of rationalization of industrial energy use has been effective. In this study, we use 80-85-90 and 90-95-00 constant price input-output table to analyze increases in industrial energy use. Using an adjusted version of structural decomposition model introduced by Chen and Rose (1990), we decompose Changes of energy use into 17 elements. We classify entire industry sector into 32 sectors including four energy sectors (coal and coal products, refined petroleum, electricity and town gas). We then analyze changes of energy use by industrial level to check differences among industrial energy demand structures. Finally, we compare three industries, electronic product manufacturing, metal manufacturing and construction, that represent technology and capital intensive, energy and material intensive and labor and capital intensive industry. As results, we find that high energy using industries make the most effort to reduce energy use. Primary metal, petrochemical and mon-metal industries show improvements in elements such as energy and material productivity, energy and material imports, energy substitution and material substitutions towards energy saving. These results imply that although those industries are heavy users of energy, they put the best effort to reduce energy use relative to other industries. We find various patterns of change in industrial energy use at industrial level. To reduce energy use, electronic product manufacturing industry needs more effort to improve technological change element while construction industry needs more effort to improve material input structure element.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.4
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• pp.41-50
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• 2017

The design of proper agitation system is requisite in biological waste treatment and energy generation plant, which is affected by viscosity, impeller types, and power consumption. In the present work, hydrogen fermentation of food waste was conducted at various operational pHs (4.5~6.5) and substrate concentrations (10~50 g Carbo. COD/L), and the viscosity of fermented broth was analyzed. The $H_2$ yield significantly varied from 0.51 to $1.77mol\;H_2/mol\;hexose_{added}$ depending on the pH value, where the highest performance was achieved at pH 5.5. The viscosity gradually dropped with shear rate increase, indicating a shear thinning property. With the disintegration of carbohydrate, the viscosity dropped after fermentation, but it did not change depending on the operational pH. At the same pH level, the $H_2$ yield was not affected much, ranging $1.40{\sim}1.86mol\;H_2/mol\;hexose_{added}$ at 10~50 g Carbo. COD/L. The zero viscosity and infinite viscosity of fermented broth increased with substrate concentrations, from 10.4 to $346.2mPa{\cdot}s$, and from 1.7 to $5.3mPa{\cdot}s$, respectively. There was little difference in the viscosity value of fermented broth at 10 and 20 g Carbo. COD/L. As a result of designing the agitation intensity based on the experimental results, it is expected that the agitation intensity can be reduced during hydrogen fermentation. The initial and final agitation intensity of 30 g Carbo. COD/L in hydrogen fermentation were 26.0 and 10.0 rpm, respectively. As fermentation went on, the viscosity gradually decreased, indicating that the power consumption for agitation of food waste can be reduced.