• The Transactions of the Korean Institute of Electrical Engineers A
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• 제50권1호
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• pp.20-27
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• 2001

In this paper, we propose a method for estimating the peak load of pole-transformer in summer season considering the degree of cooling load possession in customer. The cooling load of customer is selected as the most reliable parameter of peak load in summer season. The proposed estimation method is restricted to the aspect of load management for pole-transformer. The main concept of proposed method is that the error of peak load estimation using load regression equation reduces with considering the degree of cooling load possession in customer. We propose an index for estimation of cooling load possession in each customer. The proposed index is defined as cooling load possession in customer (CLPC) and obtained from the increment of monthly electric energy. The membership function for deciding the uncertainty of cooling load possession in customer is used. The database of pole-transformer in Korea Electric Power Corporation (KEPCO) is used for case studies. Through the case studies, we verify that the proposed method reduces the error of peak load estimation than the conventional method in domestic.

• Journal of the Korean Society for Precision Engineering
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• 제15권1호
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• pp.137-144
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• 1998

For a model system consisted of four pneumatic cylinders with strokes of 10, 20, 40 and 80 mm, investigation was carried out experimentally and numerically about the reliability of system with elastic and viscous load. The elastic load affects the performance of each cylinder in cylinder series, and changes the time lag and the velocity of the piston which makes the positioning control rather difficult. Taking the effects of the elastic load into consideration, positioning can be carried out comparatively smoothly by only adjusting the driving timing. The effect of a viscous load reduces the vibration of each moving body in the cylinder series and also reduces the over-travelled distance which happens when several cylinders move at the same time. For reasons, a positioning with a viscous load can be relatively smoothly carried out even without the timing control.

• The KIPS Transactions:PartA
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• 제11A권7호
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• pp.499-510
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• 2004

This paper proposes a heuristic load balancing algorithm for multiprocessor systems. The algorithm minimizes the number of idle links to distribute load traffic and reduces its communication cost. Each processor iteratively tries to transfer unit load to/from every neighbor processors. However, real load transfer is collectively done after complete load traffic calculation to minimize useless traffic. The proposed algorithm can be employed in various interconnection topologies with slight modifications. In this paper, it is applied to both hypercube and mesh environments. For performance evaluation, simulation studies are performed. The performance of proposed algorithm is compared to those of two well-known algorithms. The results show that the proposed algorithm always balances the loads perfectly. Furthermore, it reduces the communication costs by $70{\%}{\~}90{\%}$ in the hypercube ; and it reduces the cost by $\75{\%}$ in the mesh, compared to existing algorithms.

• Journal of the Institute of Electronics Engineers of Korea CI
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• 제42권1호
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• pp.35-44
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• 2005

This paper proposes an efficient heuristic load balancing algorithm for multiprocessor systems. The algorithm minimizes the number of idle links to distribute load traffic and reduces its communication cost. Each processor iteratively tries to transfer unit load to/from all neighbor processors. However, real load transfer is collectively done after all load traffic is calculated. This prevents useless traffic and thus reduces the overall load traffic. The proposed algorithm can be employed in various interconnection topologies with slight modifications. In this paper, it is applied to hypercube, mesh, k-ary n-cube and general graph environments. For performance evaluation, simulation studies are performed. The proposed algorithm and the well-known existing algorithms are implemented and compared. The results show that the proposed algorithm always balances the loads perfectly. furthermore, in comparison with the existing algorithms, it reduces the communication costs by 77%, 74% and 73% in the hypercube, the mesh, and k-ary n-cube, respectively.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.127-134
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• 1999

Vibration problem occurring at the metal deck floor system not only reduces the serviceability of a building but also reduces the usability of a floor system. Most problem occurring at the metal deck floor results from the human movement such as walking and running. However the vibration induced by running does not occur continuously except the special case. therefore the floor vibration due to walking was only considered on this paper,. Vibration occurring due to human walking was measured and the corresponding load function was derived through the Fast Fourier Transform(FFT)

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제22권9호
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• pp.620-627
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• 2010

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we investigated the correlation between outdoor air temperature and outlet air temperature in the system. In conclusion, from the results of the high correlation we proposed a equation of regression for the outlet air temperature in the system by using linear regression analysis.

• Journal of the Korean Society of Industry Convergence
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• 제13권3호
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• pp.169-181
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• 2010

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we proposed a simplified presumption method for the prediction of cooling and heating performance in the system. In conclusion the proposed method has been verified by comparing with the calculated value of the numerical analysis model by using nonlinear two-dimension hygroscopic question.

• Journal of the Korean Society of Industry Convergence
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• 제7권4호
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• pp.331-340
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• 2004

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we used a model for evaluation of fresh air latent heat load reduction by hygroscopic of air to earth exchange system taking into account coupled heat and moisture transfer of underground double floor space. In conclusion it shows the validity of the proposed method for a design tool and the quantitative effect of the system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제40권10호
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• pp.1-7
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• 2003

In this paper, we propose load balanced routing and wavelength assignment (RWA) algorithm for static model. The proposed algorithm arranges the routing paths over the link uniformly and assigns routing paths according to the length of routing paths orderly. Thus, the proposed algorithm can efficiently utilize the network resources. Through the computer simulation on layered-graph model, we prove that the proposed algorithm improves network throughput and reduces blocking probability comparing to first-fit algorithm [1］. Moreover, the proposed algorithm considerably reduces computational time.

• Transactions of the Korean Society of Mechanical Engineers
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• 제7권1호
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• pp.19-27
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• 1983

This paper deals with hardness and wear characteristics of ion-nitrided metal, and with ion-nitride processing which is concerned with the effects of added carbon content in gas atmosphere. A small optimal amount of carbon content in gas atmosphere increase compound layer thickness, as well as to increase diffusion layer thickness and hardness, and reduces wear rate when the applied wear load is small. It is found in the analysis that under small applied wear load, the critical depth where voids and cracks may be created and propagated is located at the compound layer, so that the abrasive wear where hardness is an important factor, is created and the existence of compound layer reduces the amount of wear. When the load becomes large, the critical depth is located below nucleation and propagation, is created and the existence of compound layer increase wear rate.