• 자원ㆍ환경경제연구
• /
• 제14권3호
• /
• pp.595-626
• /
• 2005

본 연구의 목적은 투입물 효율함수를 이용하여 한국농가의 소득계층을 대상으로 기술효율, 환경효율, 규모효율을 측정하고, Tobit 모형으로 그 결정요인을 분석하는 것이다. 본 연구는 비모수적(nonparametric) 방법에 의존하여 재화의 가격이나 최적화 행동에 관한 가정없이 투입요소와 산출량에 의존하여 기술효율을 계측한다. 생산기술은 바람직한 재화와 바람직하지 못한 오염물의 결합생산을 모형화한다. 규모불변과 강처분 하에서 평균 기술효율 수준은 0.437 이었다. 기술비효율의 원인은 순수기술비효율이 47.7%, 규모비효율은 11.3%, 환경비효율 3.2%의 순이다. 규모체증 상태에서 생산농가는 전체농가의 70%를 점유하고 규모체감 상태에서 생산농기는 전체농가의 27%에 이른다. 효율성을 결정하는 요인으로 소득계층이 높을수록 중장기 부채가 높을수록 단위면적당 질소배출량이 높을수록 기술효율은 높았고, 경지면적당 농업경영비가 높을수록 기술효율은 저하되었다. 환경효율에서는 BOD 배출량, 단위면적당 기계도입, 자본의 생산성 유의적이고 음(-)으로 나타나, 청정기술이 아닌 단순한 기계화의 확대는 환경효율을 악화시키는데 영향을 주고 있음을 시사한다.

• 한국콘텐츠학회논문지
• /
• 제22권5호
• /
• pp.165-173
• /
• 2022

최근, 4차 산업혁명 미래기술 및 투자전략의 관점에서 정보통신업의 특화된 서비스를 제공하기 위한 경쟁이 치열하다. 정보통신 관련 기술혁신이 기업의 생산성 증대, 부가가치를 창출하며 경제성장의 발전에도 중추적인 역할을 담당한다고 볼 수 있다. 이에 정보통신업의 효율적인 경영관리가 중요한 시점이다. 본 연구는 DEA를 활용하여 코스닥 상장된 정보통신업의 상위 30% 기업을 대상으로 경영효율석을 분석하며 효율적인 운영을 위한 기업의 투사값을 제시하며 벤치마킹 기업의 참조집합을 확인한다. 코스닥 상장된 정보통신업의 CCR 효율성, BCC 효율성, 순위, 규모효율성(SE), 규모수익성(RTS)을 평가하였다. 분석결과 CCR효율성이 1인 업체는 14개 기업, BCC효율성이 1인 업체는 10개 기업으로 분석되었다. 규모수익성은 IRS가 4개의 기업, CRS가 13개, DRS가 13 기업으로 분석되었다.

• 디지털융복합연구
• /
• 제11권5호
• /
• pp.119-133
• /
• 2013

본 연구의 목적은 독점적 지위로 운영되는 발전회사의 환경효율성 분석을 통하여 미래의 녹색경영, 지속경영에 대한 기관 효율성 향상에 기여하고자 하는 것이다. DEA 분석이 가진 내재적인 부족함을 보완하기 위해 C 발전회사 산하 6개의 기관을 직접 방문하여 담당 전문가로부터 DMU의 환경효율성을 위한 인터뷰 자료도 활용하였다. 투입요소로는 경영효율성에서는 비용과 종업원 수를 환경효율성으로는, CO2, NOx, 용수 사용량이 사용되었다. 산출요소로는 연간 총발전량, 판매수익이 사용되었다. 분석에는 규모수익불변(CRS, Constant Return to scale)투입지향의 DEA모형과 VRS(Various Return to Scale)모형을 이용하였다. CRS 분석에 의하면 0.923, BCC 분석으로는 0.969로 나타났으며 7개의 DMU가 효율적인 것으로 나타났다. 산출요소별 비효율적인 투입요소에서는 NOx가 CO2 보다 낮았다. 이는 전력발전에 있어 NOx는 물론 CO2에 관한 효율성이 개선되어야 한다는 것을 보여주고 있다. 환경비효율성을 줄이기 위해서는 결국 신재생에너지와 연료 전지 등 대체에너지원이 지속적으로 개발되어져야 한다.

• 한국항해항만학회지
• /
• 제34권9호
• /
• pp.719-726
• /
• 2010

As the competition among the container terminals in Korea has become increasingly fierce, every terminal is striving to increase its investments constantly and lower its operational costs in order to maintain the competitive edge and provide satisfactory services to terminal users. The unreasoning behavior, however, has induced that substantial waste and inefficiency exists in container terminal production. Therefore, it is of great importance for the terminal to know whether it has fully used its existing infrastructures and that output has been maximized given the input. From this perspective, data envelopment analysis (DEA) provides a more appropriate benchmark. This study applies three models of DEA to acquire a variety of analytical results about the operational efficiency to the Korean container terminals. According to efficiency value analysis, this study first finds the reason of inefficiency. It is followed by identification of the potential areas of improvement for inefficient terminals by applying slack variable method and giving the projection results. Finally, return to scale approach is used to assess whether each terminal is in a state of increasing, decreasing, or constant return to scale. The results of this study can provide terminal managers with insight into resource allocation and optimization of the operating performance.

• 대한족부족관절학회지
• /
• 제23권2호
• /
• pp.52-57
• /
• 2019

Purpose: An ingrown nail is common in military trainees who are exposed to highly demanding activities. Although the matrixectomy procedure has been the main treatment modality, several drawbacks may follow after the procedure, such as infection, periostitis, and continued pain that causes a delayed return to duty. This study examined the outcomes of a simple partial nail extraction with the hypothesis that this procedure may bring an earlier return to duty, lower the perioperative complications, and produce a comparable recurrence rate. Materials and Methods: The medical records of patients who had surgical treatment for an ingrown nail in the authors' institution between April 2016 and December 2017 were reviewed retrospectively. Under the inclusion and exclusion criteria, 28 patients with a simple partial nail extraction (group A) and 29 patients with a partial nail extraction with matrixectomy (group B) were investigated. As the clinical outcome, the visual analogue scale (VAS) and satisfaction score, time to return to duty, complications, and recurrence rate were checked and compared between the groups. Results: The VAS scores of group B were significantly higher during the first (p<0.001) and second (p=0.026) follow-up week than group A. The time to return to duty was shorter in group A (7.8 days) than group B (10.1 days), and this difference was significant (p<0.001). Group B had five patients with complications, whereas group A had none (p=0.028). No differences in the recurrence rate (p=0.197) and patient satisfaction (p=0.764) were found between the groups. Conclusion: In this study, simple partial nail extraction in military trainees resulted in lower postoperative pain, lower complication rates, and earlier return to duty than the procedure with matrixectomy. Military trainees are temporarily exposed to highly demanding activities. Thus, a satisfactory outcome would be expected with simple partial nail extraction without performing a radical procedure, such as a matrixectomy.

• The Korean Journal of Pain
• /
• 제35권1호
• /
• pp.97-105
• /
• 2022

Background: Percutaneous transforaminal endoscopic discectomy (PTED) has been widely used in the treatment of lumbar degenerative diseases. Epidural injection of steroids can reduce the incidence and duration of postoperative pain in a short period of time. Although steroids are widely believed to reduce the effect of surgical trauma, the observation indicators are not uniform, especially the long-term effects, so the problem remains controversial. Therefore, the purpose of this paper was to evaluate the efficacy of epidural steroids following PTED. Methods: We searched PubMed, Embase, and the Cochrane Database from 1980 to June 2021 to identify randomized and non-randomized controlled trials comparing epidural steroids and saline alone following PTED. The primary outcomes included postoperative pain at least 6 months as assessed using a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). The secondary outcomes included length of hospital stay and the time of return to work. Results: A total of 451 patients were included in three randomized and two non-randomized controlled trials. The primary outcomes, including VAS and ODI scores, did not differ significantly between epidural steroids following PTED and saline alone. There were no significant intergroup differences in length of hospital stay. Epidural steroids were shown to be superior in terms of the time to return to work (P < 0.001). Conclusions: Intraoperative epidural steroids did not provide significant benefits, leg pain control, improvement in ODI scores, and length of stay in the hospital, but it can enable the patient to return to work faster.

• 한국물환경학회지
• /
• 제22권5호
• /
• pp.905-912
• /
• 2006

In this paper, simulation methods of the system dynamics model developed by Das et al. (1997) for activated-sludge wastewater treatment plants are illustrated in an attempt to determine the operating rules and the policies related to capacity expansion of an activated-sludge wastewater treatment plant. For existing conditions, the analyses were performed by varying activated-sludge return rate to observe changes in effluent water quality and treatment efficiency. The effluent water quality is also analyzed for various average daily inflow conditions and activated-sludge return rates. As a result, without expanding the aeration tank, maximum average daily inflow that can satisfy the effluent water quality standard of BOD $0.02kg/m^3$ was determined as $2,840m^3/hr$, subject to 100% of activated-sludge return rate while other factors remain constant. When the activated-sludge return rate is less than 100%, expansion of the aeration tank is necessary and minimum sizes of the aeration tank to satisfy the effluent water quality standard were determined for various activated-sludge return rates. In addition, the total operating and maintenance as well as unit treatment cost regression equations for activated-sludge wastewater treatment plants are suggested by using the cost data that are obtained from Water and Wastewater Division, Ministry of Environment. The regression analyses showed that the economies of scale phenomena exist in the operating and maintenance costs of activated-sludge wastewater treatment plants.

• 공학교육연구
• /
• 제27권1호
• /
• pp.50-62
• /
• 2024

This study examined how emotion regulation strategies specifically function in the interpersonal conflict coping strategies of engineering students. For this purpose, a interpersonal conflict coping strategies and emotion regulation strategies scale was used for 548 engineering students. Multiple regression analysis was conducted. Among the emotion regulation strategies, the "return to body" strategy was related to understanding, validation, focusing, and the "stop action" strategy. In particular, the "stop action" strategy was closely related only to the "return to body" strategy. Among interpersonal conflict coping strategies, the dominating strategy used both positive emotion regulation strategies, such as high refocus on planning, and negative emotion regulation strategies, such as other-blame. Additionally, among negative conflict coping strategies, it was confirmed that both aggression and negative emotional expression, which seem to have similar attributes, share a common feature of having high difficulty in emotional clarity. However, in the case of negative emotional expression, it is characterized by a lack of putting into perspective and high other-blame. On the other hand, the agression strategy seemed to have different characteristics, such as high self-blame and low return to body. By investigating the relationship between interpersonal conflict coping strategies and specific emotion regulation strategies, this study provides implications for education and intervention on which specific emotion regulation strategies need to be cultivated for engineering students to improve their interpersonal conflict resolution capabilities.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제15권4호
• /
• pp.21-29
• /
• 2010

As the target area of this study, the coal mine site of Dongwon Sabuk mine.,ltd. is located in the remote mountainous region. To purify the acid mine water contaminated with heavy metals, a pilot-scale plant was built at the surrounded area of a mine shaft and operated to simulate active treatment system that could not only possibly setup the facility in a small available area, but also has a high efficiency. According to the various conditions of basin sequence, existence of sludge return, and lime injection position, six different types of treatment series were investigated in terms of treatment efficiency. As a result, the aluminum concentrations of the most effluents were in the range of 0.005~0.030 mg/L, which was too low to compare. The manganese concentration in the treated water were in the range of 3~9 mg/L, not following any regular trend. As found in the results of iron concentration, the case of addition of oxidation and sludge return steps showed higher efficiency than the others. As a standpoint of the installation of full-scale physicochemical treatment facility, the experimental results showed that the batch of oxidation and high density sludge return processes are existed and neutralization was followed by oxidation, had a stable treatment efficiency.

• 한국IT서비스학회지
• /
• 제15권2호
• /
• pp.51-63
• /
• 2016

In this study, we conducted a comparative analysis of R&D investment efficiency and operational efficiency of IT firms using Data Envelopment Analysis (DEA). We categorized thirteen sample firms into two groups-IT manufacturing and IT service-after an extensive literature review on IT industry classification. We adopted an output-oriented two-stage DEA model suggested by Banker et al. (1984) with total asset and R&D investment as input variables. Then, we constructed investment efficiency and operational efficiency by using Return on Equity (ROE) and Return on Asset (ROA) as intervening variables and operating income and Earnings Per Share (EPS) as output variables. The outcome of the analysis is summarized as follows. First of all, IT manufacturing firms were more efficient (57% on average) than IT service firms. To be specific, IT service firms showed decreasing returns to scale (DRS) with diseconomy of scale. In contrast, IT service firms showed higher operational efficiency (81.5% on average) than IT manufacturing firms. Also, we conducted a Mann-Whitney U test to compare the output of IT service firms and IT manufacturing firms. Lastly, we found a negative correlation ($R^2$ = -.754) between R&D investment efficiency and operational efficiency which infers the trade-off between two constructs