• 한국CDE학회논문집
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• 제13권3호
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• pp.235-242
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• 2008

This paper proposes a method for improving the process plan quality by use of dimensional tolerances. Dimensioning and tolerancing plays a key role in manufacturing process plan because the final part must ensure conformance with the dimensions and tolerances in its drawing. As a first step for the improvement of process plan quality, two resultant tolerances in design and process plan should be compared each other, and so a tolerance chart is used for acquisition and comparison of the two tolerances. In addition to two kinds of design and manufacturing tolerances, operational sequences or paths for the resultant dimension and tolerance are additionally recognized for measuring the quality of process plan quantitatively. Rooted tree is applied to find the related paths for the manufacturing resultant tolerances. A quality coefficient is defined by the components of two tolerances and their relations, the paths related to manufacturing resultant tolerances and the difficulty of an operation. In order to improve the quality of manufacturing process plan, the paths that two kinds of tolerances are the same or different in the rooted tree are recognized respectively and a method for tolerance rearrangement is developed. A procedure for improving the quality is suggested by combining the coefficient and the tolerance rearrangement method. A case study is applied to illustrate the efficiency of improvement method.

• 한국정밀공학회지
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• 제21권10호
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• pp.50-56
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• 2004

Finishing is the final process in molds manufacturing and consumes much process time. Also, it influences on surface quality of molds. But, there are few systematic methods to control the process. In this work, basic experiments were carried out to study the machining characteristics of the finishing tools. From the experiments, critical surface roughness and wear coefficient are suggested to reduce the number of finishing steps and to plan a systematic finishing procedure. Comparison experiments were carried out between the expert's method and the new method, which is based on the results of this research. From the experiments, it is verified that the systematic method takes less time and generates less form error in the machined surface than the worker's method.

• 상하수도학회지
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• 제33권1호
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• pp.17-29
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• 2019

This study developed prediction models of chlorine bulk decay coefficient by each condition of water quality, measuring chlorine bulk decay coefficients of the water and water quality by water purification processes. The second-reaction order of chlorine were selected as the optimal reaction order of research area because the decay of chlorine was best represented. Chlorine bulk decay coefficients of the water in conventional processes, advanced processes before rechlorination was respectively $5.9072(mg/L)^{-1}d^{-1}$ and $3.3974(mg/L)^{-1}d^{-1}$, and $1.2522(mg/L)^{-1}d^{-1}$ and $1.1998(mg/L)^{-1}d^{-1}$ after rechlorination. As a result, the reduction of organic material concentration during the retention time has greatly changed the chlorine bulk decay coefficient. All the coefficients of determination were higher than 0.8 in the developed models of the chlorine bulk decay coefficient, considering the drawn chlorine bulk decay coefficient and several parameters of water quality and statistically significant. Thus, it was judged that models that could express the actual values, properly were developed. In the meantime, the chlorine bulk decay coefficient was in proportion to the initial residual chlorine concentration and the concentration of rechlorination; however, it may greatly vary depending on rechlorination. Thus, it is judged that it is necessary to set a plan for the management of residual chlorine concentration after experimentally assessing this change, utilizing the methodology proposed in this study in the actual fields. The prediction models in this study would simulate the reduction of residual chlorine concentration according to the conditions of the operation of water purification plants and the introduction of rechlorination facilities, more reasonably considering water purification process and the time of chlorination. In addition, utilizing the prediction models, the reduction of residual chlorine concentration in the supply areas can be predicted, and it is judged that this can be utilized in setting plans for the management of residual chlorine concentration.

• 간호행정학회지
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• 제5권2호
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• pp.237-251
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• 1999

The purpose of this study is to suggest successful strategies through which the effect of the information system of a hospital can be forecasted at the nursing department. In order to set up successful strategies, in the first place, both the methods of CSF(Critical Success Factor: Rockart, 1979) and ULD(User-Led Development) method and the method suggested by the Korea Productivity Center were applied. In order to measure the improvement of nursing productivity, the Dissonance theory was used. The data were collected from 100 employees serving at the clinic department of Kwangju Patriots' and Veterans' Hospital from July 4 to July 25, 1998 with reference to all 222 cases, for sampling work; then the part of the efficiency of the treatment or management of hospital business - simplification of the process of the treatment of hospital business and reduction of the time of the treatment of hospital business were measured; and in order to forecast organizational behavior, 100 cases of organization behavior were analysed, based on the well structured, questionnaires. In order to forecast the user's organizational behavior, a tool(Ronald. 1988; Stephen, 1982: Senn, 1992: Olsen, 1980: Anderson, 1988: Kim. 1992: Cho. 1994) to measure the extent or degree of the user's recognition or understanding whose reliability coefficient is 0.63 was used: and regarding the items expected by the users concerning the convenience of the system, a tool created by Bernadett, Szajna and Richard W. Scamell(1993) whose reliability coefficient is 0.88 was used. And finally, those data were analysed, utilizing the statistical package of SPSS/PC 6.0. successful strategies are suggested as follows: 1. In order that the Kwangju Patriots' and Veterans' Hospital's purpose can be successful through its strategic, information system, the quality of its services should be elevated. and for elevating the quality of medical services, elevation of the quality of medical expertism or specialty is an important factor in determining such quality. 2. In order to make the hospital information system to be successful, the hospital's top manager should participate in the effort making it successful with helping hands of the members or personnel of the hospital. 3. In order to make users participate in the hospital information system, it is prerequisite that all nurses in a hospital should voluntarily participate in the system 4. In order to reduce the expense, the time in coping with business per duty should be reduced by 10${\sim}$33.23%. The time of the direct nursing care which added value is relatively high should be elongated in order to elevate the quality of hospital services. 5. Since the introduction and spread of the hospital information system are influenced by the duration in the experience of computer use, the user of the hospital information system should have a plan to receive well-planned computer education. Finally it is suggested that the forecast of long-term productivity through a review of the user's expectation of the system should be inspected and tested through continuous studies of its effectiveness.

• 대한환경공학회지
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• 제39권12호
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• pp.714-722
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• 2017

수질오염총량관리제도(이하 총량제)는 하천의 목표수질을 달성하기 위해 유역에서 배출되는 오염물질의 총량을 관리하는 제도이다. 유역에서 배출되는 오염물질의 허용총량은 수질모델을 활용하여 산정하며, 이과정에서 오염부하량은 발생, 배출, 유달부하량으로 구분할 수 있다. 유달부하량은 배출부하량과 유달율의 곱으로 계산되며 유달율은 유역에서 배출된 오염물질이 하천의 특정지점에 도달하는 비율로 정의된다. 본 연구에서는 Hwang(2016) 등이 제시한 기준유량 조건의 유달율 추정방법을 영강유역에 적용하고 QUALKO2 수질모델의 수질 입력자료를 생성하여 기준유량 조건의 유달율 산정방법(식 (3))과 평균 개념의 유달율 산정 방법(식 (2))의 비교분석을 통해 유달율 추정방법에 대한 검증 연구를 수행하였다. 연구결과, 유달율 함수식은 식 (2)와 식 (3) 모두 사용 가능하나, 배출계수 적용에 따라 방법론을 달리할 필요가 있다. 식 (2)를 사용할 경우는 배출계수를 저수량, 평수량 구분없이 1로 동일하게 사용해야 하며, 식 (3)을 사용할 경우는 기술지침에서 정한 배출계수(저수량 0.15, 평수량 0.5)를 적용해야 할 것으로 판단된다.