• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.2
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• pp.85-95
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• 2019

The internal environment in pig house is closely related to the animal productivity. In addition, it is important to consider a working environment inside the pig house due to high gas and dust concentrations. The poor working environment inside the pig house can cause health problems including respiratory diseases. To analyze the working environment, it is important to evaluate the ventilation efficiency to effectively remove harmful gases and dust. The purpose of this study is to develop a 3D CFD model to analyze the working environment in the pig house. CFD model was validated by comparing air temperature distributions between CFD computed and field measured data. The average air flow rate at the pig height was 40.1 % lower than the working height when incoming air was concentrated on upper layer by the installed ventilation system on the experimental pig house. Using the validated CFD model, the regional ventilation efficiency was computed by the TGD(tracer gas decay) method at the pig and working heights. There was a difference of ventilation efficiency on 14 % between the air stagnated section and the rest sections. Stagnated gas concentration can be effected by animal and human health.

• KDI Journal of Economic Policy
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• v.26 no.2
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• pp.143-178
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• 2004

For a thorough accounting for economic growth, it is desired to include the working hours and the efficiency of labor as production factors in addition to the number of workers and human and physical capital stocks. This paper estimates the distribution of weekly working hours of total workers as a continuous variable using the maximum likelihood method, estimates the efficiency of labor as a function of working hours using wage statistics, and by combining these results, estimates the labor efficiency index in Korea for the period 1963~2003. Estimation results show that the efficiency of labor was maximized when the weekly working hours was 40 hours, and the average annual growth rate of the labor efficiency for the period 1963~2003 was 0.14 percent.

• Journal of Korean Port Research
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• v.14 no.3
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• pp.259-267
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• 2000

This study aims to analyse the coefficient used to estimate the quay capacity per year at the container terminal. The capacity of the container terminal is composed of the capacity at the quay side and the other working conditions at the back of the quay side. But when we refer the capacity of the container terminal, generally we used capacity as that of the container terminal. To estimate the quay capacity independently of the working conditions at the back of quay side, we calculate the quay capacity as th product of working hours per year, productivity of container crane and relate other coefficients, such that berth utilization, crane utilization and efficiency. So that coefficients are properly defined to reflect the other working conditions. If we calculate the quay capacity by the product of working hours modified by the berth utilization and crane productivity modified by the crane utilization and efficiency, the meaning of that coefficients must be strictly defined. So there could be no confusion to apply that coefficients to calculate the quay capacity. In this study, we exclusively define the meaning of the berth utilization, crane utilization and efficiency according to the internal-meaning of thats in the function to calculate the quay capacity. And compare each coefficients by decomposing the working hours at the terminal.

• Korean Institute of Interior Design Journal
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• no.18
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• pp.23-30
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• 1999

Nowadays, large-scale office buildings have been multistoried, mechanized, and functioned with economic growth. These buildings have improved and developed technical and designated respects in varied society. Even though these buildings are in improved situation, working places which are one of the most important parts have not developed enough their functions and shapes. Working environments that were ignored have come a big issue to rise efficiency and productivity. Working functions and work's opinions did not examine and analyze because of careless cognition of working places. In these reason, workers are engaged in inconvenient surroundings that already set improper way or not to develope environments that obstructs productivity. Working places which were ignored in the past have come a big issue to rise productivity and efficiency. Now, the goal of this research is to reform working places more efficient and functional by examining by examining working environment and proper arrangements.

• Journal of environmental and Sanitary engineering
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• v.5 no.1
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• pp.83-92
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• 1990

Adapting two step aeration system to a waste water treatment of W-paper manufactory as Full-Scale Plants, we drew a following conclusion from its practical working. 1. Because BOD removal efficiency was 20% in A-Stage, 90% in B-Stage and total removal efficiency was 97%. It worked treatment plant well and was suitable for effluent water standard as well. Because COD removal efficiency was 42% in A-stage, 71% in B-stage and the total removal efficiency was 94% COD control was possible in effluent water quality. 2. Treatment efficiency according to a load capacity was average 20% in 1.401 BOD kg/m3/d load of A-Stage and average 90% in 0.273 BOD kg/$\textrm {m}^3$ / d load of B-Stage. 3. Treatment efficiency according to a ratio of F/M was 2.657--5.024 kg BOD/kg MLSS/d in A-Stage and BOD removal efficiency was 16-261 in the same stage. The ratio of F/M was 0.068-0.094 kg BOD /kg MLSS/d and BOD removal efficiency ratio was 85-94%. Therefore treatment efficiency could be kept stably and volume of aeration tank could be reduced wholly. 4. Treatment efficiency according to MLSS appeared BOD 20%. COD 42%, in A-Stage and removal efficiency appeared BOD 90%, COD 71% in B-Stage. They were suitable for plan condition. 5. Because of working of complemented treatment plant by AB-Process. 20,000,000 Won a month was saved than the ordinary working cost. Therefore, it was assumed that invested cost could be recollected in 19 months or so consequently.

• Korean Journal of Agricultural Science
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• v.33 no.2
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• pp.159-166
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• 2006

Threshing loss was increased due to dropping of the threshing efficiency when the 4 row head-feed combine harvested 5 row rice to improve harvesting performance of a combine. Reasonable design criteria were examined to determine the ranges of both of feed rate and the length of threshing drum for the 4 row head-feed combine being used as a 5-row combine. Harvesting performance increased as working width or working speed increased, it resulted in 15% increase when the working width increased from 4 row to 5 row. Harvesting operations of the 4 row combine performed normally in the 4 row rice in threshing loss less than 1%, however, threshing loss increased to 2.25% in the 5 row due to poor threshing efficiency. The length of threshing drum was increased from 710 mm to 810 mm as well as the speed of crop feed chain was increased from 0.61 m/s to 0.75 m/s so as to improve the poor threshing efficiency resulted from the enlarged working width from the 4 row to the 5 row, which would decrease threshing loss less than 1%.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.597-603
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• 2016

In this paper a comparative thermodynamics analysis is carried out for organic Rankine cycle (ORC) and ammonia-water Rankine cycle (AWRC) utilizing low-grade heat sources. Effects of the working fluid, ammonia concentration, and turbine inlet pressure are systematically investigated on the system performance such as mass flow rate, pressure ratio, turbine-exit volume flow, and net power production as well as the thermal efficiency. Results show that ORC with a proper working fluid shows higher thermal efficiency than AWRC, however, AWRC shows lower mass flow rate of working fluid and lower pressure ratio of expander than ORC.

• The KSFM Journal of Fluid Machinery
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• v.18 no.4
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• pp.5-12
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• 2015

Several working fluids for Organic Rankine Cycle(ORC) were recommended by many researchers. However, the recommended optimal working fluids were not exactly same because the operating conditions of ORC and application were different. The major parameter to select the working fluid for ORC was the temperature of available thermal energy. In this study, low-grade thermal energy was used for the heat source for ORC and the appropriate working fluids were searched among 26 candidate working fluids. The requirements to be a working fluid for ORC were reviewed and the cycle analysis for simple cycle was conducted with $75^{\circ}C$ and $35^{\circ}C$ at the turbine inlet and exit, respectively. R600, R601, toluene were best candidates if the system could work without leaking the working fluid. Next, R236ea, R245ca, R245fa were recommended because they are not inflammable working fluids as well as better efficiency.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.227-232
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• 2010

In this paper we consider the multi-robot system that collects target objects spread in an unexplored environment. The robots cooperate each other to improve the capability and the efficiency. The robots attract or intimidate each other as behaviors of bacterial swarms or particles with electrical moments. The interactions would increase the working efficiency in some environments but it would decrease the efficiency in some other environments. Therefore, the system needs to adapt to the working environment by adjusting the strengths of the interactions. The strengths of the interactions are expressed as sets of gene codes that mean the weights of each kind of attracting or intimidating vectors. The proposed system adjusts the gene codes using evolutional strategy. The proposed approach has been validated by computer simulation. The results of this paper show that our inter-swarm interacting strategy and optimizing algorithm improves the working efficiency, adaptively to the characteristics of environments.

• Korean Institute of Interior Design Journal
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• no.32
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• pp.64-71
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• 2002

Today, term of ‘industrial society’means the totally changing society by new technical innovation through the Industrial Revolution begun in England at the mid-nineteenth century and it made social structure centering agricultural culture change with industrial culture with expansion of goods by the massive production. Information working area has to bo a space not just for improving business efficiency in industrial society but for developing efficiency in working in harmony with the information and structural aspects based on computer and communication technology. There are two kinds of environmental elements of working space : the tangible ones are the area and the structure of working space, lights, network, layout and information machines in office, the intangible ones are a feeling of satisfaction of management and arrangement of office information machines capability of information delivery, common ownership of documents and their files, the security and connection between office workers, and harmony. According to the wave of information begun from the late twentieth century, structural layout of working area has become various by the working type through network of new developed information communication machines. But it is hard to apply them in actually.