• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.107-115
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• 2006

The existing DLC system functionally has two defects. One is it has to be controlled by operators whenever customer's portion of loads are increased more than predefined objected load. Therefore, it may be possible for propagating uncontrolled loads if operators make a mistake. The other one is that currently used DLC algorithm is usually focused on ON/OFF load control not concerning about reliving participated customer's inconvenience. Therefore, that is a major obstacle to attract customer participating in demand response program. This paper represents direct load control system using active database. By using active database, DLC system can control customer's load effectively without intervening of operator. And by using dynamic programming based on the order of priority for DLC algorithm, it is possible to maximize participating customer's satisfaction.

• Fire Science and Engineering
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• v.33 no.5
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• pp.130-139
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• 2019

This study identified the level of task stress experienced by fire protection system management workers and analyzed the effects of task stress on job satisfaction and proposed future response. First, task stress according to background cause showed differences in relation to age, position, monthly salary, total career, license, and task, but there was no difference in relation to academic background. Second, of the sub-parameters of stress, physical environment, task demand, organizational system, lack of reward, and workplace culture have negative effects on job satisfaction as stress increases, while interpersonal relation conflict and job insecurity do not have any effect. In the future, it will be necessary to investigate the empirical causes of work overload and to study organization-level stress relief measures.

• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.89-97
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• 2011

In semantic web information system like ontology that access distributed information from network, efficient query processing requires an advanced caching mechanism to reduce the query response time. P2P network system have become an important infra structure in web environment. In P2P network system, when the query is initiated, reducing the demand of data transformation to source peer is important aspect of efficient query processing. Caching of query and query result takes a particular advantage by adding or removing a query term. Many of the answers may already be cached and can be delivered to the user right away. In web environment, semantic caching method has been proposed which manages the cache as a collection of semantic regions. In this paper, we propose the semantic caching technique in cluster environment of peers. Especially, using schema data filtering technique and schema similarity cache replacement method, we enhanced the query processing efficiency.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.135-142
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• 2008

Recently, the mobile Internet is rapidly changing environment in a user's web server performance requires frequent connection is difficult because the proper response is needed to improve the performance of web services engine. Therefore, the goal of this paper is to improve the performance of web services for the installation of additional access to users regardless of tomcat servlet container and process the request and to shorten processing time of SOAP (Simple Object Access Protocol) message of the server structure to of for web mobile services. The web-sever structure is consists of user demand receiver, web document processor, SOAP protocol processor, NBTM(Non-Blocking and Thread Manager) manager, session manager. The system fully supports a standard web-service protocol, reduces the message processing time and communication overhead of mobile web-service system in Web 2.0 and overhead of server, and confirms the improvement of capability by comparing and evaluating Web 2.0 standard mobile web-service system through delaying achievement evaluation by the experiment of realization in Web 2.0 environment.

• Design & Manufacturing
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• v.16 no.1
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• pp.55-61
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• 2022

As meters become digital and smart, energy data such as electricity, gas, heat, and water can be accurately and efficiently measured with a smart meter, providing consumers with data on energy used, so that real-time demand response and energy management services can be utilized. Although it is developing from a simple metering system to a smart metering industry to create a high value-added industry fused with ICT, illegal counterfeiting of electronic meters is causing problems in intelligent crimes such as manipulation and hacking of SW. The meter not only allows forgery of the meter data through arbitrary manipulation of the SW, but also leaves a fatal error in the metering performance, so that the OIML requires the validation of the SW from the authorized institution. In order to solve this problem, a quantitative confirmation device was developed in order to eradicate the act of cheating the fuel oil quantity through encoder pulse operation and program modulation, etc. In order to prevent the act of deceiving the lubricator, a device capable of checking pulse forgery was developed, manufactured, and verified. In addition, the performance of the device was verified by conducting an experiment on the meter being used in the actual field. It is judged that the developed quantitative confirmation device can be applied to other flow meters other than lubricators, and in this case, accurate measurement can be induced.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.37-44
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• 2022

Plug-in Hybrid electric vehicles (PHEV) show great potential to reduce gas emission, improve fuel efficiency and offer more driving range flexibility. Moreover, PHEV help to preserve the eco-system, climate changes and reduce the high demand for fossil fuels. To address this; some basic components and energy resources have been used, such as batteries and proton exchange membrane (PEM) fuel cells (FCs). However, the FC remains unsatisfactory in terms of power density and response. In light of the above, an electric storage system (ESS) seems to be a promising solution to resolve this issue, especially when it comes to the transient phase. In addition to the FC, a storage system made-up of an ultra-battery UB is proposed within this paper. The association of the FC and the UB lead to the so-called Fuel Cell Battery Electric Vehicle (FCBEV). The energy consumption model of a FCBEV has been built considering the power losses of the fuel cell, electric motor, the state of charge (SOC) of the battery, and brakes. To do so, the implementing a reinforcement-learning energy management strategy (EMS) has been carried out and the fuel cell efficiency has been optimized while minimizing the hydrogen fuel consummation per 100km. Within this paper the adopted approach over numerous driving cycles of the FCBEV has shown promising results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.5
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• pp.321-328
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• 2015

In recent years, there has been an increasing demand to apply the new IACS(International Association of Classification Societies) standards for ice and polar-classed ships. For ice-class vessel propulsion system, the ice impact torque design criterion is defined as a periodic harmonic function in relation to the number of the propeller blades. However, irregular or transient ice impact torque is assumed to occur likely in actual circumstances rather than these periodic loadings. In this paper, the reliability and torsional vibration characteristics of a comparatively large six-cylinder marine diesel engine for propulsion shafting system was examined and reviewed in accordance with current regulations. In this particular, the transient ice impact torque and excessive vibratory torque originating from diesel engine were interpreted and the resonant points identified through theoretical analysis. Several floating ice impacts were carried out to evaluate torque responses using the calculation method of classification rule requirement. The Newmark method was used for the transient response analysis of the whole system.

• Ecology and Resilient Infrastructure
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• v.2 no.1
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• pp.12-21
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• 2015

Social demand for ecological engineering and technology has increased in tandem with national economic growth in order to improve the environmental capacity of civil infrastructures. To meet this demand, the Korean Society of Ecology and Infrastructure Engineering (KSEIE) was established in January 2013 and has contributed to the development of ecological engineering technologies. However, the establishment of an educational system for human resources training in ecological engineering is still at an early stage, and it is imperative to develop a curriculum for producing the human resources that can understand and apply ecological principles and functions and that is equipped with the abilities required for ecological conservation, restoration, and creation. As part effort, the KSEIE held a forum, entitled Founding the Education for Ecological Engineering, to discuss the establishment of the education system for ecological engineering in Korea. In this paper, based on the discussions and suggestions made during the forum, we analyzed the current status of ecological engineering education in various disciplines - civil and construction engineering, biology and environment, and landscape planning - in domestic universities, and attempted to seek possible solutions based on the cases of foreign universities. Generally, ecology and other application curricula are taught as fragmented subjects and fields in domestic universities. The development of new education strategies and systematic curricula for multidisciplinary education, ecological response to climate change, and the expansion of research fields is required.

• KSBB Journal
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• v.22 no.6
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• pp.438-442
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• 2007

A biosensor using electrochemically-active bacteria (EAB) enriched in three-electrode electrochemical cell, was developed for the determination of biochemical oxygen demand (BOD) in wastewater. In the electrochemical cell, the positively poised working electrode with applying a potential of 0.7 V was used as an electron acceptor for the EAB. The experimental results using artificial and raw wastewater showed that the current pattern generated by the biosensor and its Coulombic yield were proportional to the concentration of organic matter in wastewater. The correlation coefficients of BOD vs Coulombic yield and $BOD_5$ vs Coulombic yield were 0.99 and 0.98, respectively. These results indicate that the biosensor enriched with the EAB capable of transferring electrons directly toward the electrode can be utilized as a water-quality monitoring system due to a quick and accurate response.

• The Journal of Fisheries Business Administration
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• v.22 no.2
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• pp.53-74
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• 1991

Interest on ocean environment has increased with the development of industrialized activities. Public marine resorces are defined broadly to include fish stocks, beaches, marine waters, recreational fishing, biota, waterfowls, shorebirds, seabirds and marine mammals But, it is not easy to analyze compensation for injury to publicly owned marine resources because the claimants do not exist clearly and the economic methodology of damage on public goods is not developed fully. This paper introduces basic idea of welfare economic theory and environmental legislation to the research question : How the economics and law can be applied to the case of damage on publicly owned marine resource. The paper discusses the concepts of willingness to pay (WTP) and willingness to accept (WTA). It is accepted generally that WTA is correct concept of welfare change in the case of damaged public goods. Four methods (compensating variation, equivalent variation, compensating surplus, equivalent surplus of measuring welfare changes are compared. Compensating variation(CV) is the best measure of welfare changes are compared. Compensating variation(CV) is the best measure of welfare changes caused by environmental damage. Vartia (1983) showed CV could be measured from the ordinary demand function using the differential equations. This paper also provides an overview of the emerging U.S. and Korea legal system for compensation for natural resource damages, with particular emphasis on U.S. legal system under Comprehensive Environmen-tal Response Compensation and Liability Act (CERCLA). These regulations are to include two different types of standardized procedures for assessing natural resources injury : Type A or simplified assessment techniques for small releases ; and Type B protocols that would include detailed and extensive assessment methodologies for major releases. Type A procedures are specified by Natural Resources Damage Assessment Model for Coastal and Marine Environment (NRDAM/CME) of the U.S. CERCLA provides a legal 'legitimization for the use of economic-based nonmarket valuation in the courts and have introduced appropriate and accurate nonmarket valuation methods based on willingness to-pay for damage assessment. By briefly reviewing economic theory and environmental legislation, we hope to help provide a better understanding of the compensation process and the economics of publicly owned marine resources in the U.S. and to integrate the economics and law of natural resources valuation into a single comprehensive package in Korea.