• 보건의료산업학회지
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• 제9권3호
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• pp.57-67
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• 2015

Objectives : This study has analyzed the relationship between DEA efficiency of costs-patient revenues, productivity per value added and management performance in mental hospitals. Methods : The relationship between DEA efficiency of costs-patient revenues, the productivity per value added and management performance were conducted with correlation analysis and logistic regression. Results : The DEA efficiency of costs-patient revenues had a significant causal relationship with the value added ratio to gross revenue indexing productivity per value added. On the other hand, it was revealed that the operating margin indexing management performance had a slightly significant causal relation with DEA efficiency of costs-patient revenues. Conclusions : The material costs should be focused on the management stability of mental hospitals, and known to the desirable management orientation for the higher efficiency of costs-patient revenues.

• 한국병원경영학회지
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• 제13권4호
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• pp.1-26
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• 2008

This study examines the statistical relationship between medical specialists and managerial performance, using regression analysis with the number of medical specialists per 100 beds as the independent variable and the managerial performance index as the dependent variable. Managerial performance index incorporated the number of out-patients per specialist, the number of in-patients per specialist, the volume of revenue per specialist, the number of beds per specialist, and the average length of stay. To compare different groups of hospitals, dummy variable was applied to five groups of hospitals according to size: 100-299 beds, 300-599 beds, 600-899 beds, 900-1199 beds, and more than 1200 beds. The data consisted of 181 general hospitals with more than 100 beds, which included 28 public hospitals, 73 corporate hospitals, 64 university hospitals and 16 private hospitals. Of those, 87 hospitals were located in big cities and 94 hospitals in medium to small cities. This study used hospitals from the Korean Hospital Association, and data published in 2004. The collected data sample was analyzed using the SPSSWIN 12.0 version, and the study hypothesis was tested using regression analysis. The findings of this study are summarized as follows: Hypothesis 1 predicting a negative effect of the number of medical specialists on the number of out-patients per specialist was supported with statistical significance. The analysis of dummy variable showed causality in all the hospital groups larger than the group of 100-299 beds. Hypothesis 2 predicting a negative effect of the number of medical specialists on the number of in-patients per specialist was supported with statistical significance. The analysis of dummy variable showed causality in the hospital group of 300-599 beds when compared to the group of 100-299 beds. Hypothesis 3 predicting a negative effect of the number of medical specialists on the volume of revenue per specialist was not supported. However, the analysis of dummy variable showed that the volume of revenue per specialist increased in the hospital groups of 600-899 beds, 900-1199 beds, and over 1200 beds, when compared to the group of 100-299 beds. Hypothesis 4 predicting a negative effect of the number of medical specialists on the average length of stay was supported with statistical significance. The analysis of dummy variable showed causality in the hospital group of 300-599 beds, when compared to the group of 100-299 beds. Results of this study show that the number of the medical specialists per 100 beds is an important factor in hospital managerial performance. Most hospitals have tried to retain as many medical specialists as possible to keep the number of patients stable, to ensure adequate revenue, and to maintain efficient managerial performance. Especially, the big hospitals with greater number of beds and medical specialists have shown greater revenue per medical specialist despite the smaller number of patients per medical specialist. Findings of this study explains why hospitals in Korea are getting bigger.

• Journal of Biosystems Engineering
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• 제30권6호통권113호
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• pp.321-326
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• 2005

Tractor performance was analyzed using the data from 226 Korean-made and 107 imported tractors tested at the National Institute of Agricultural Engineering for the 25-year period from 1980 through 2004. The performance analysis included the specific volumetric fuel consumption (svfc), power per unit weight and traction coefficient evaluated from the viewpoint of PTO power level. No significant performance improvement has been made for the Korean-made tractors over the last 25 years. The average svfc for the maximum PTO power has increased by only $2.1\%$ from 1980 to 2004, resulting in 2.86 kW${\cdot}$h/L in 2004. The average maximum PTO and drawbar power per unit weight of ballasted tractors were 1.38 and 1.19 kW/kN in 2000-2004, indicating $14.0\%$ and $5.9\%$ decreases respectively from 1980 to 2004. The traction coefficient has increased by $23.1\%$ over the 25 years, resulting in 0.68 in the 2000-2004 period. Poor performance improvement was also observed from the imported tractors. In the 2000-2004 period, average svfc for the maximum PTO power, PTO power per unit ballasted weight, drawbar power per unit ballasted weight and traction coefficient of the imported tractors were respectively 3.0 kW${\cdot}$h/L, 1.34 kW/kN, 1.13 kW/kN and 0.68. PTO and drawbar power per unit weight were lower in imported tractors than the Korean-made tractors. Comparing the test results with those of tractors less than 37 kW tested at the Nebraska Tractor Test Laboratory from 1981 to 2002, the Korean-made tractors have exhibited better performance in terms of power per unit weight. However, poor performance in the svfc and traction coefficient was observed. The average svfc and traction coefficient of the Korean-made tractors were respectively $86.4\%$ and $83.7\%$ of the tractors tested at the NTTL over the same period.

• 한국컴퓨터정보학회논문지
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• 제20권7호
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• pp.85-90
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• 2015

This study surveyed 152 publicly traded companies to investigate group-performance based pay practices and its impacts on labor productivity. Compared a benchmark survey from Department of Labor, those companies show higher introduction rates, especially in small-to-medium sized companies. They also tend to pay profit-sharing bonus more in the form of company stocks and differentiate individual bonuses more by department performance than individual performance. The impact of group-performance based pay on labor productivity is positive and statistically significant. Economic value added per person in those companies adopting group-performance based pay tends to be higher and increases with the coverage of employees under the pay plan. It also reveals that the years after the play adoption are negatively associated with labor productivity.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권5호
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• pp.511-518
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• 2015

As the cost-per-byte of SSDs dramatically decreases, the introduction of SSDs to Hadoop becomes an attractive choice for high performance data processing. In this paper the cost-per-performance of SSD-based Hadoop cluster (SSD-Hadoop) and HDD-based Hadoop cluster (HDD-Hadoop) are evaluated. For this, we propose a MapReduce performance model using queuing network to simulate the execution time of MapReduce job with varying cluster size. To achieve an accurate model, the execution time distribution of MapReduce job is carefully profiled. The developed model can precisely predict the execution time of MapReduce jobs with less than 7% difference for most cases. It is also found that SSD-Hadoop is 20% more cost efficient than HDD-Hadoop because SSD-Hadoop needs a smaller number of nodes than HDD-Hadoop to achieve a comparable performance, according to the results of simulation with varying the number of cluster nodes.

• 한국항행학회논문지
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• 제11권3호
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• pp.274-280
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• 2007

초 광대역 신호는 상대적으로 낮은 주파수에서 매우 넓은 대역폭을 갖는 방사 스펙트럼을 특징으로 하고 있다. 본 논문에서는 잡음과 동일채널간섭 채널에서 M-ary 상관 수신기 구조로 된 초 광대역 시스템의 비트 오율, 패킷 오율, 데이터 처리율 성능을 분석한다. UWB 시스템의 성능을 평가하기 위하여 하나 이상의 펄스 위치 변조 신호로 구성된 UWB 통신 파형을 사용하였다. 본 논문에서 사용된 M-ary PPM 신호는 시스템 성능 해석의 간략화를 위하여 균일하게 상관된 PPM 신호를 정의하였다. 시스템 성능의 해석을 통하여 무선 채널 에러는 처러율 성능을 감소시키며 hybrid ARQ 기법을 통하여 효과적으로 증가시킬 수 있음을 알 수 있었다. 또한, 성능 개선 기법과 사용된 파라미터를 통하여 초 광대역 시스템의 데이터 처리율 비교를 수행하였다. 성능 평가 과정을 통하여 무선 채널과 hybrid ARQ 기법의 영향을 신호 대 잡음 전력비에 따른 PER 및 처리율을 평가하였다.

• 한국산학기술학회논문지
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• 제10권11호
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• pp.3110-3114
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• 2009

회전자 온도 변화는 유도 전동기 제어기 설계에 있어서 중요한 쟁점이다. 문헌에서, 수많은 연구들이 회전자 온도 변화를 고려하지 않는다면, 그에 기인한 심각한 성능 저하를 언급해왔다. 하지만, 이러한 연구들은 추종 성능 관점에서 주로 Field-oriented 제어기에 초점을 두고 있으며, 단위 전류당 최대 토크 제어기와 같이 최적 제어의 경우에서의 성능에 미치는 회전자 온도 변화의 영향에 대한 연구는 전무하다. 본 연구는 회전자 온도가 시간에 따라 변화함에 따라, 단위 전류당 최대 토크 제어기의 성능에 어떻게 영향을 미치는지를 조사한다. 이를 위해, 두 가지 방법으로 단위 전류당 최대 토크 제어기의 목적이 성취되는 지를 점검한다. 즉, 요구되는 토크를 발생시키면서 동시에 최소 가능한 고정자 전류를 필요로 하는 것이다. 실험실 실험결과는 추종 성능과 단위 전류당 최대 토크 조건이 회전자 온도가 변화함에 따라 심각한 영향을 받으며, 결과적으로 단위 전류당 최대 토크 제어기의 성능저하를 초래함을 보여준다.

• Journal of Information Technology Applications and Management
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• 제18권4호
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• pp.55-79
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• 2011

This study attempts to examine the factors affecting the introduction of e-Business systems and also, to assess the effects of various e-Business systems on firm performance. Empirical analysis is carried out with firm data of 2009, which is collected from Firm Activity Survey of Statistics Korea. Firm performance is measured by four indexes; operating income per employee, value added per employee, return on assets, and return on sales. Empirical results indicate that a firm is more likely to introduce any e-Business system as its size and its assets per employee are larger and as its ratio of labor compensations to operating costs is lower. Additionally, a firm with higher skill levels and more fruitful management experiences is more likely to have any e-Business system. In general, it appears that the presence of e-Business, especially enterprise resources planning, has positive effects on the firm performance.

• Journal of information and communication convergence engineering
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• 제18권4호
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• pp.222-229
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• 2020

Recent multi-core processors for smart devices use per-core dynamic voltage and frequency scaling (DVFS) that enables independent voltage and frequency control of cores. However, because the conventional task scheduler was originally designed for per-core DVFS disabled processors, it cannot effectively utilize the per-core DVFS and simply allocates tasks evenly across all cores to core utilization with the same CPU frequency. Hence, we propose a novel task scheduler to effectively utilize percore DVFS, which enables each core to have the appropriate frequency, thereby improving performance and decreasing energy consumption. The proposed scheduler classifies applications into two types, based on performance-sensitivity and allows a performance-sensitive application to have a dedicated core, which maximizes core utilization. The experimental evaluations with a real off-the-shelf smart device showed that the proposed task scheduler reduced 13.6% of CPU energy (up to 28.3%) and 3.4% of execution time (up to 24.5%) on average, as compared to the conventional task scheduler.

• KIEE International Transactions on Power Engineering
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• 제3A권1호
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• pp.17-26
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• 2003

In this paper, the comparative steady-state operating performance analysis algorithms of the stand-alone single-phase self-excited induction generator (SEIG) is presented on the basis of the two nodal admittance approaches using the per-unit frequency in addition to a new state variable de-fined by the per-unit slip frequency. The main significant features of the proposed operating circuit analysis with the per-unit slip frequency as a state variable are that the fast effective solution could be achieved with the simple mathematical computation effort. The operating performance results in the simulation of the single-phase SEIG evaluated by using the per-unit slip frequency state variable are compared with those obtained by using the per-unit frequency state variable. The comparative operating performance results provide the close agreements between two steady-state analysis performance algorithms based on the electro-mechanical equivalent circuit of the single-phase SEIG. In addition to these, the single-phase static VAR compensator; SVC composed of the thyristor controlled reactor; TCR in parallel with the fixed excitation capacitor; FC and the thyristor switched capacitor; TSC is ap-plied to regulate the generated terminal voltage of the single-phase SEIG loaded by a variable inductive passive load. The fixed gain PI controller is employed to adjust the equivalent variable excitation capacitor capacitance of the single-phase SVC.