• Plant Journal
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• v.13 no.2
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• pp.46-51
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• 2017

In this study, the boiler efficiency and the change of boiler combustion state with the burner operation of the uppermost layer of 870MW opposite fired coal boiler were measured. Test results showed that the boiler efficiency was high in the order of the uppermost layer simultaneous operation of the front and rear burners, the front burner, and the rear burner operation. When the front and rear burners were operated simultaneously, the heat absorption rate of water walls in the boiler furnace was uniform at four side, and the temperature deviation of the left and right steam on the convection front surface decreased. As the heat absorption rate of the boiler improved, the loss of boiler exhaust gas decreased and the coal supply amount decreased by 8 tons/hour compared to the operation of the rear burner. This will contribute not only to the reduction of fuel cost but also to the reduction of greenhouse gas emissions.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2002.11a
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• pp.301-306
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• 2002

In Japan, the vacancy rates of office buildings have been at high in big cities since 1992. This problem is especially acute in Tokyo, where it is estimated that over 2.27 million square meters of office floor area will be oversupplied in 2003: big urban redevelopment projects will be completed in 2003. Under these circumstances, International Cooperative Research and Development on Sustainable Urban Management by Conversion of Buildings, called “SUMCOB”, has been carried out. This research aims to regenerate urban areas by converting redundant offices into flats, although instances of conversion are still very few in Japan. This paper introduces part of current results by SUMCOB, and discusses legal problems with conversion and basic capacity of vacant offices in Tokyo. It has been confirmed that there are no constraints concerned with Real Estate Registration Law (although it requires the change of the registration after conversion). and City Planning Law. However, some criteria are incompatible with Building Standard Law and Fire Service Law if the use of the building is changed from offices to flats. Typical incompatibility between offices and flats is lightening. If the buildings do not satisfy criteria for flats, the cost of renovation works for conversion will increase. To examine the basic capacity of vacant office buildings for conversion, field surveys in Tokyo have carried out at three areas: Kodenmacho (Chuo-ku), Toranomon (Minato-ku), and Iwamonocho (Chiyoda-ku). They are typical office areas that are included in center core of Tokyo. In Chuo-ku, the oldest commercial area in Tokyo, textile merchants have been located their headquarters. In Minato-ku, many rental office buildings have been located and several large scale redevelopments are advancing. Chiyoda-ku includes Marunouchi area, which is the prime office area in Japan. Thirty percent of the buildings in survey areas suffer from over twenty percent vacant floor rate, and fifty five percent were constructed before 1990. Especially most of buildings over forty percent vacant floor rate were constructed in 1980s. Vacant office problems haven't been seen in old buildings in Tokyo yet. The number of dwelling units made from office space will influence the conversion scheme. Seventy percent of the office buildings in survey areas have floor area of less than two hundred square meters. If they have been subdivided into two bedrooms type or three bedrooms type, the number of dwelling units in a floor would be less than three. The difficulty of conversion planning derives from frontage size, depth size, and their proportion. The five categories are proposed to grasp actual requirements for converting offices into flats.

• Research in Community and Public Health Nursing
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• v.6 no.2
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• pp.173-182
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• 1995

Primary health care(PHC) has been established since A Health Law for rural residents has been legislated in 1980 following the WHO declaration, 'Health for All 2000'. in 1978. PHC services are presently assumed to be provided by 2038 Community Health Practitioners(CHP) to about 28% out of rural population in Korea. Most CHPs have confronted the adaptation process to the community being practiced although a CHP's role is to evoke community participation for the improvement of their health by themselves. So the purpose of this study is to describe and explain of the commitment of CHPs into the community. Data were collected by direct interview and tape-recording under subjects' permission till theoretical saturation were occured from 6 CHPs. The subjects were 41 years old and have served in the community for 9 years in average. Main questions and concepts were explored from data according to the procedure of the grounded theory methodology. The results are as follows. 1) The number of the main concepts were twenty four that identified Motive, Desire, Personal characteristics, Unfamiliarity, Denial, Feeling of isolation, Self-sacrifice, Kindness, Patience, Assimilation, Respect for the residents, Support by the family, Support by the residents, Achievement, Acceptance of realities, Use of resources, Inducement of cooperation from the residents, Changes of the difference from time orientation between CHP and residents, Attitude as a official, Technical support, Cost management, Satisfaction level, Acknowledgement by the residents and discrepancy. 2) The twenty four concepts were categorized to seven groups such as Motivation, Feeling of Heterogeneity, Self-discipline, Social support, Induced changes in the attitudes of residents, Familarity and Persistent discrepancy. 3) The categorized groups were analyzed on the base of the Causal Conditions, Central Phenomena, Contexts, Intervening Conditions, Action / Interaction Strategies, and Consequences. Central phenomenon in this study was identified to be the feeling of heterogeneity. Community health practitioners experienced unfamiliarity and denial from the community and felt themselves isolated in the first. In time, they won the trust of residents by their efforts including self-sacrifice, kindness, patience, and assimilation. Afterward, practitioners got self-confidence and familiarity with lesser feeling of heterogeneity. Nevertheless, practitioners could not commit themselves completely because of the persistent discrepancy between CHP and residents. 4) On the commitment process, the CHPs' feeling of heterogeneity were decresed and social support increesed and newly evolved induced change of residents through the continuous interaction between CHP and them The contribution of this study would be concluded as follows. 1) It is expected that effective strategies for more rapid committment into the community can be developed based on this study. 2) More easy committment would be possible for the newly appointed CHP through understanding of the committment process identified on this study.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.3-11
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• 2011

There are several causes to recalculate the contract amount in public construction projects. Among them, the escalation clause was introduced in 1969 and now the condition to recalculate the cost is effective after 90 days from the date of contract and the rate of fluctuation should be more than 3% from the date of bidding. The two calculation methods for the rate of fluctuation are item-adjustment and index-adjustment. According to the results of investigation into 4 public institutions and 163 projects, all of them have used the method of index-adjustment and the rate of projects that spend over 6 months obtaining the approval of contract amount adjustment is more than 90%. The reason for spending lots of time is caused by problems of the calculation method on the price fluctuation rate. Therefore, it is necessary that the calculation method should be diversified to cope with the problems and a option of the builder should be expanded as well. Furthermore, if the way to apply correction factors to construction price index and average index based on the producer and consumer price index made by the bank of Korea is added, then the duration will be reduced without additional expenses. This study proposed the diversification of the calculation method using price fluctuation rate and builders' expanded options as improvement on the managerial method of Price Fluctuation System for the prompt and efficient contract amount adjustment.

• Korean Journal of Construction Engineering and Management
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• v.10 no.5
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• pp.113-122
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• 2009

The domestic construction market started to expand steadily since 1970s. The building market which utilizes a sandwich panel with advantages of economical construction expenses and convenient construction has grown rapidly in recent years. However, the companies which specialize in constructing sandwich panels are relatively small or medium size, compared with other construction companies. As a result, studies on the improvement of productivity have not been conducted sufficiently. In this study, the construction sites of sandwich panel are investigated, and the work processes by each team are analyzed. Additionally, the productivity and the construction cost of each work group are analyzed by constructing a model using the Web-Cyclone. It analyzed sensitivities about change of productivity and work costs following in processing place of the panel which is one of the productivity effect factors, so it assayed the optimized productivity by each work group and work costs. Analysis showed that 30% of productivity has improved compared with the factory processing work group, and analysis of work costs showed that about 15% of work costs was increased. Also sensitivity analysis of opening ratio showed that the work costs optimization will be accomplished when about 20% of opening was processed from the factory.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.146-156
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• 2013

Recently, to reflect the various needs of customers in the apartment field, the customized apartment has emerged. From the point of the customer, customized apartments have the definite advantage of being able to guarantee more customer options. On the other hand, from the point of the project manager, there are significant risk factors, with increase of management factors, construction delays, etc. The reasons for this are, to date, the insufficient systematic analysis of the project, and the lack of experience of similar projects. This study provides the waste factors of each phase in a customized apartment project. A survey and interview are conducted to achieve the waste factors using MUDA methodology; a process of the project was analyzed; and a factor of each process was identified. Also, AHP(Analytic Hierarchy Process) are used, to evaluate the waste factors in project stages. The AHP results show that "Design change" and "Inappropriate intervention in construction process" ranked highly in the waste factors. The results of our research will provide a countermeasure that addresses waste factors in similar projects, and contributes to reducing the extra cost and time in new projects.

• Journal of Environmental Policy
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• v.7 no.4
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• pp.1-34
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• 2008

It is recognized that RPS(Renewable Portfolio Standard) and FIT(Feed-in Tariff) are two main policy instruments to promote Renewable Electricity(RE). The Korean Government announced in 2008 that RE promotion scheme will be changed to RPS from current FIT system in 2012. But we believe RPS is inferior to FIT for promoting less developed technologies such as photovoltaics or wind power. This is because the achievement of RE promotion in countries adopting RPS is markedly worse than that in European counties or Janpan adopting FIT. If the policy change is inevitable, when considering the lessons from Japan's failure as well as supporting the less developed technologies, it is recommended that either the market should be divided into several technology and scale categories, or more RPS-Credit per kWh should be assigned to the photovoltaic and wind power than instead of letting the all technologies compete in the "open category". It is also recommended that (1) Renewable Energy Promotion Fund(tentative name) based on a part of current energy related tax revenue should be introduced, or (2) cost of supporting the Renewable Electricity should automatically be transferred into the electricity bill of electricity consumers following the German System.

• Journal of the Korean GEO-environmental Society
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• v.11 no.6
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• pp.5-20
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• 2010

One-dimensional equivalent linear site response analysis is widely used in practice due to its simplicity, requiring only few input parameters, and low computational cost. The main limitation of the procedure is that it is essentially a linear method, in which the time dependent change in the soil properties cannot be modeled and constant values of shear modulus and damping is used throughout the duration of the analysis. Various forms of modified equivalent linear analyses have been developed to enhance the accuracy of the equivalent linear method by incorporating the dependence of the shear strain with the loading frequency. The methods are identical in that it uses the shear strain Fourier spectrum as the backbone of the analysis, but differ in the method in which the strain Fourier spectrum is smoothed. This study used two domestically measured soil profiles to perform a series of nonlinear, equivalent linear, and modified equivalent linear site response analyses to verify the accuracy of two modified procedures. The results of the analyses indicate that the modified equivalent linear analysis can highly overestimate the amplification of the high frequency components of the ground motion. The degree of overestimation is dependent on the characteristics of the input ground motion. Use of a motion rich in high frequency contents can result in unrealistic response.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.3
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• pp.11-17
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• 2009

The drop impact reliability comes to be important for evaluation of the life time of mobile electronic products such as cellular phone. The drop impact reliability of solder joint is generally affected by the kinds of pad and reflow number, therefore, the reliability evaluation is needed. Drop impact test proposed by JEDEC has been used as a standard method, however, which requires high cost and long time. The drop impact reliability can be indirectly evaluated by using high speed shear test of solder joints. Solder joints formed on 3 kinds of surface finishes OSP (Organic Solderability Preservation), ENIG (Electroless Nickel Immersion Gold) and ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) was investigated. The shear strength was analysed with the morphology change of intermetallic compound (IMC) layer according to reflow number. The layer thickness of IMC was increased with the increase of reflow number, which resulted in the decrease of the high speed shear strength and impact energy. The order of the high speed shear strength and impact energy was ENEPIG > ENIG > OSP after the 1st reflow, and ENEPIG > OSP > ENIG after 8th reflow.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.54-59
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• 2010

This paper present to study the guidance system as localization technique using sensor fusion and line tracking technique using virtual line for AGV(autonomous guided vehicle). An existing AGV could drive on decided line only. And representative guidance systems of such guidance system are magnet-gyro guidance and wired guidance. However, those have had the high cost of installation and maintenance, and the difficulty of system change according to variation of working environment. To solve such problems, we make the localization system which is fused with a laser navigation and gyro, encoder. The system is robust against noise, and flexible according to working environment through sensor fusion. For line tracking of laser navigation without wire guidance, we set the virtual line in program, and design the driving controller based on difference of angle and distance between AGV's position and decided virtual line. To experiment, we use the AGV which is made by ourselves, and experiment the line tracking repeatedly on same experimental environment. In result, maximum distance error between decided virtual line and AGV's position was less than 49.93mm, and we verified that the proposed system is efficient for line tracking of actual AGV.