• 대한환경공학회지
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• 제38권8호
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• pp.403-410
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• 2016

고속도로의 건설시 많은 자원이 투입되고 있으나 이를 정량적으로 산정하여 관리하고 있지 않다. 본 연구에서는 LCA기법을 MFA에 접목하여 고속도로의 건설시 투입되는 총 자원요구량을 구간별로 직접 자원요구량과 간접 자원요구량으로 구분하여 산정하였다. 그 결과 직접 자원요구량은 모래 2.27E + 04 ton/km, 석회암 1.02E + 04 ton/km 및 자갈 4.47E + 03 ton/km 순으로 나타났으며, 간접 자원요구량은 자갈 2.75E + 04 ton/km, 철 9.80E + 03 ton/km 및 석탄 9.74E + 03 ton/km 순으로 나타났다. 따라서 모래, 석회암 등과 같은 직접 자원요구량이 높은 자원들은 시공현장에서 과량투입 방지와 같은 자원관리가 필요할 것으로 판단되며, 철을 비롯한 희유금속(크롬, 니켈) 및 석탄과 같은 간접 자원요구량이 높은 자원들도 자원관리 측면의 추가적인 연구가 필요할 것으로 판단된다.

• 자원환경지질
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• 제41권5호
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• pp.497-507
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• 2008

본 연구는 국내 5대 수출 품목 중 하나이며, 국내 주요 수출품의 원자재로서 지속가능한 자원관리의 파급효과가 큰 철강을 대상으로 히든플로우와 물질집중도를 MIPS방법론을 이용하여 정량화하였다. 2005년에 4.8천톤의 철강재와 17.6백만달러(2000년 기준)의 부가가치를 생산하기 위해 71백만톤의 윈재료와 18백만Toe의 에너지를 사용하였다. 이러한 원재료와 에너지사용으로 인한 천연자원사용량은 TMR(total Material Requirement, 총물질요구량) 245백만톤, water 1524백만톤, air 34백만톤이었다. 그리고 material intensity, 즉 철강재 1톤을 생산하기 위해서 TMR 4.3톤, water 28톤, air 0.5톤의 자연자원이 사용되었다.

• Industrial Engineering and Management Systems
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• 제4권1호
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• pp.23-35
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• 2005

This paper aims to develop a practical finite capacity MRP (FCMRP) system based on the needs of an automotive parts manufacturing company in Thailand. The approach includes a linear goal programming model to determine the optimal start time of each operation to minimize the sum of penalty points incurred by exceeding the goals of total earliness, total tardiness, and average flow-time considering the finite capacity of all work centers and precedence of operations. Important factors of the proposed FCMRP system are penalty weights and dispatching rules. Effects of these factors on the performance measures are statistically analyzed based on a real situation of an auto-part factory. Statistical results show that the dispatching rules and penalty weights have significant effects on the performance measures. The proposed FCMRP system offers a good tradeoff between conflicting performance measures and results in the best weighted average performance measures when compared to conventional forward and forward-backward finite capacity scheduling systems.

• Journal of Biosystems Engineering
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• 제4권2호
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• pp.46-52
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• 1979

The water delivery hose for agricultural pump is getting popular in rural areas in korea. Friction head loss, discharge, and power requirements were measured in various discharge for different material and diameter of hose to get basic data for economical use in agricultural pump. The results attained in this study were as follows ; 1. Friction head loss increased significantly as the velocity increased, and the difference of velocity between the different diameter of hose was bigger than that between materials, which was resulted in the increase of the friction head loss. 2. Friction head loss in the case of that the velocity with 2m/sec was constant was about 3.53 to 4.01 m/100m in the diameter 3" and about 2.30 to 3.10 m/100m in the diameter 4". Material A of diameter 3" showed the maximum value 8.4m/100m in Reynolds number $2.0\times10^5$, 4" got the minimum value 2.24m/100m, the difference between these values was bigger than 6m per 100 meters in the friction head loss. 3. Darcy-Weisbach formular with friction coefficient [f] calculated by Nikurades formular in the smooth pipe or with friction coefficient [f] calculated on the base of C value 125 in Hazen-Williams formular was available in friction head loss of the water discharger hose in rural areas. 4. Total head increased as friction head loss increased , meanwhile total discharge decreased, and 20 percents of energy was more saved in Material C 4″pipe than Material A 3″pipe in the view point from the discharge per unit power requirement, this phenomenon suggested that long distance pipe would be advantage in larger diameter pipe for save of energy. for save of energy.

• 한국경영과학회지
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• 제26권1호
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• pp.71-85
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• 2001

This paper considers a cost model for a U-shaped manufacturing cell formation which incorporates a required number of machines and various material flows together under multi-part multi-cell environment. The model is required to satisfy both the specified operation sequence of each part and the total part demand volume, which are considered to derive material handling cost in U-shaped flow line cells. In the model several cost-incurring factors including set-up for batch change-over, processing time for operations of each part, and machine failures are also considered in association with processing load and capacity of each cell. Moreover, a heuristic for a good machine layout in each cell is newly proposed based on the material handling cost of each alternative sequence layout. These all are put together to present an efficient heuristic for the U-shaped independent-cell formation problem, numerical problems are solved to illustrate the algorithm.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.21-24
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• 2008

In this paper, we introduce the status of concentration photovoltaic system. Currently, crystalline silicon solar has 90% of total solar market. But in a few years, the concentration solar system is expected to be main one because cost increasement of silicon material is not stabilized unit now. At 2012, it will take 5% of the whole solar market. Less expensive, material requirement and high system efficiency give high driving force for intensive research on concentration system. It is time for us to initiate the basic study and evaluate the long term stability compared to crystalline silicon system. The detail discussion will be shown in the following paper.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(4)
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• pp.182-187
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• 1996

Deformation characteristics of miniature plate tensile specimens have been studied to develop the thickness requirement and a correlation to estimate the mechanical properties of bulk material from miniature specimen data. The material used was a SA 508 C1.3 reactor pressure vessel steel and the thicknesses of miniature tensile specimens varied from ().12 m to 2 mm. The effects of thickness on the tensile deformation properties such as strength, ductility, and necking characteristics were analyzed. The yield and ultimate tensile strengths were independent of specimen thickness when the thickness was larger than about 0.2 mm. The uniform and total elongations decreased as the specimen thickness decreased. It was also observed that the uniform strain component in the width direction decreased with decrease in the specimen thickness, however, that in the thickness direction was rather constant in total thickness range studied. Based on this observation and a relationship between the necking angle and the ratio between strain components, a correlation between the uniform elongations of miniature specimen and standard specimen was derived. The uniform elongations calculated by this new correlation agreed well with the measured values.

• 대한두경부종양학회지
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• 제15권1호
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• pp.52-60
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• 1999

Objectives: For investigation of the differentiation between transient and permanent hypocalcemia, we focused on a postoperative calcium requirement and an interval of normalization in serum hypocalcemic level and studied for the causes of postoperative hypocalcemia. Material and Method: Postthyroidectomy hypocalcemia was studied in 193 patients who were admitted from January, 1991 to December, 1998 and underwent lobectomy, subtotal thyroidectomy or total thyroidectomy. We compared postoperative serum calcium, phosphate and ionized calcium levels among three groups which were lobectomy, subtotal thyroidectomy and total thyroidectomy, respectively. Result: All patients revealed postoperative decline in serum calcium and ionized calcium, especially, the lowest serum calcium level was seen in 48 hours after surgery. Serum calcium level was returned to normal in five to six postoperative days in most patients. But 24 patients required calcium supplementation due to symptomatic hypocalcemia. In this series, we discovered that the important period for monitoring of serum calcium level was 24 to 96 hours after surgery. If the calcium replacement therapy was not required in the first 72 hours after surgery, it would not be needed during the remainder of the patient's hospital course. Symptomatic transient hypocalcemia was 22 cases(11.4%) and permanent hypocalcemia was 2 cases(1%). Conclusion : We found that hypoalbuminemia, preoperative hyperthyroidism and impairment of blood supply to parathyroid were the main causes of postthyroidectomy hypocalcemia. We also thought that the interval from initial medication to normalization in serum calcium level, and the increase of requirement in calcium and vitamin D were the important factors for differentiation between transient and permanent hypocalcemia.

• 부모자녀건강학회지
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• 제6권1호
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• pp.1-17
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• 2003

Thus, I studied Health services supplied by local health centers and the requirements of the inhabitants visiting the health care facilities. The purpose of this study was to provide basic material for the establishment of Health care policy and the development of health care businesses. The target places for this study were 4 health centers; Chungrang-Gu, Nowon-Gu, Eunpyung-Gu, Songpa-Gu, with 509 mothers who were visiting the Centers. The question items of this study concerned a total of 124 health-related services provided by the Health Centers. The data was collected for a total of 92 days; July 1st~September 30th, 1999. 800 questionaries were distributed and 559 answered, 509 were analyzed finally. The collected data were processed using the SAS program to get mean, standard deviation, percentage. Open questions were made to reveal the opinions of mothers using the health care center. The results were as follows : 1. Among the participants of the study, 49.7% were 25~29 years of age, 84.3% were house wives by current occupation, 56.2% were from 4~6 person households. 52.1 were educated at a high school level, and 43.6% were educated at a collage level. 2. The highest percentage(53.6%) of the users were spontaneous in their utilization of health care center. The major reason for using the Health care center is that it is free to 65.8% of those covered and of low cost to 19.3% of those covered. 3. The satisfaction level of those using the health care center appeared to be generally high. The general average value showed up as $3.027{\pm}0.519$. 4. The level of recognition of the value of the heath care center services was high, particularly in the basic item of diagnoses of pregnancy, particularly in the basic item of diagnoses of pregnancy. However, the satisfaction level of health care education In pregnancy is low at 20~40%. In the meantime, the level of recognition in breast- feeding benefits is high at 76.8%. 5. The rate of realizing health care center's service campaign was generally low at 10~20%. 41.3 of the people knew the advertizing material of the health care centers. 32.4% of the people knew the advertizing material of the health care centers. 32.4% of the people knew the campaign of health care center for importance of breast-feeding benefits. 30.1% of the people knew the campaign for testing congenital mechanism disease. In the meantime about 50% was recognised the health care centers campaign for the importance and time of infants vaccination. 6. The need for enhancement of health care center services was shown to be high as $3.266{\pm}0.676$ as an average, chicken pox vaccination being the most highly requested at $3.565{\pm}0.587.$. 7. Among the open questions, the additional service to be provided were as follows ; increase of campaign of health care center services, furnishing advertizing books in public locations, providing shuttle bus service to the health care centers, extension of desire for preventative injections, rest and play areas for the children of the families serviced, consultation rooms, etc.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2008년도 제33회 펄프종이기술 국제세미나
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• pp.47-70
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• 2008

Cost efficiency is today the primary requirement in the paper and board industry. This has led therefore, to a greater preponderance of products with specifically designed functionality to take account of current industry needs. Continually increasing machine coating speeds together with these new coating colour components have put more emphasis on the importance of the correct rheology and water retention of the coating colours to achieve good runnability and end product quality. In the coating process, some penetration of the aqueous phase, to the base paper or board must occur to anchor the pre-coating to the base or the topcoat to the pre-coat. The aqueous phase acts as a vehicle not only for the binder, but also for the other components. If this water or material penetration is not controlled, there will be excessive material shift from the coating colour to the base, before immobilization of the coating colour will stop this migration. This can result in poor machine runnability, unstable system and uneven coating layer, impacting print quality. The performance of rheology modifiers or thickeners on the coating color have tended to be evaluated by the term, "water retention". This simple term is not sufficient to explain their performance changes during coating. In this paper we are introducing a new concept of "material retention", which takes note of the total composition of the coating colour material and therefore goes beyond the concept of only water retention. Controlled material retention leads to a more uniform z-directional distribution of coating colour components. The changes that can be made to z-directional uniformity will have positive effects on print quality as measured by surface strength, ink setting properties, print gloss, mottling tendency. Optical properties, such as light scattering, whiteness and light fastness delivery should also be improved. Additionally, controlled material retention minimizes changes to the coating colour with time in re-circulation giving less fluctuation in quality in the machine direction since it more closely resembles fresh coating for longer periods. Use of the material retention concept enables paper and board producers to have more stable runnability (i.e. lower process costs), improved end product quality (i.e. better performance of used chemicals) and/or optimized use of coating colour components (i.e. lower total formulation cost)