• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.4
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• pp.21-27
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• 1975

In this paper, a procedure for deriving of multiple fault detection test sets is presented for fan-out reconvergent combinational logic networks. A fan-out network is decomposed into a set of fan-out free subnetworks by breaking the internal fan-out points, and the minimal detecting test sets for each subnetwork are found separately. And then, the compatible tests amonng each test set are combined maximally into composite tests to generate primary input binary vectors. The technique for generating minimal test experiments which cover all the possible faults is illustrated in detail by examples.

• The KSFM Journal of Fluid Machinery
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• v.19 no.5
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• pp.42-49
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• 2016

Aerodynamic analysis of a low-voltage electric motor has been performed with various inlet vent shapes. Effects of inlet vent shape on aerodynamic performance of a motor cooling fan have been investigated numerically using three-dimensional Reynolds-averaged Navier-Stokes equations. The k-${\varepsilon}$ turbulence model was used for the analysis of turbulence. The finite volume method and unstructured tetrahedral grids were used in the numerical analysis. Optimal grid system in the computational domain was selected through a grid-dependency test. From the results of the flow analysis, considerable energy loss by flow separation was observed in the flow passage. It was found that mass flow rate through the cooling fan in the low-voltage motor can be increased by modifying the inlet vent shape. And, some inlet vent shapes were suggested to improve the aerodynamic performance of the motor cooling fan.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.386-391
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• 2009

In this study, the numerical study has carried out to analyze the factors of the efficiency decrease at backward flow situation in an axial fan with adjustable blades. The analysis is carried out the pitch angle $36^{\circ}$ on the forward flow and the pitch angle $-26^{\circ}$ on the backward flow. The numerical results show that the air flow rates of the pitch angle $36^{\circ}$ and $-26^{\circ}$ are respectively calculated to 285 CMM and 212 CMM. The results are similar to the experimental results carried out by Chang, and have made the maximum error of 10.6% when compared with the experimental results. The important reason of the fan efficiency decrease is that axial fan used for this study was designed to use for the forward flow. As the results, the pitch angle $-26^{\circ}$ has occurred the recirculation around the impeller blade, impeller cover and stator.

• Journal of Veterinary Clinics
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• v.24 no.1
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• pp.56-58
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• 2007

This study was attempted to find appropriate surgery for gill cover curling disorder in arowana. Gill cover curling is a usual clinical findings in arowana, which often lead to death of the fish by dyspnea. Two different surgical methods were implemented in this study for gill cover by using cutting and incising fm-like fer two silver arowana. The surgery was identified to be successful since the fish healthily recovered. This experiment demonstrated that gill cover curling can be cured by using surgery.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.973-974
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• 2014

대형 전동기의 주요 소음원은 전자기 소음과 냉각/통풍 시스템 소음이며, 이 중 냉각/통풍 시스템이 전체 소음에 큰 영향을 미친다. 본 논문에서는 대형 전동기의 저소음 냉각/통풍 시스템 개발을 위해 저소음 냉각 팬을 개발하고 팬 커버 내부의 유로를 개선하였다. 유동해석은 상용 CFD 소프트웨어를 이용하였으며 팬 커버 내의 scroll 형상 및 air guide, baffle 의 유무에 따라 팬 커버의 압력손실을 계산하였다. 해석을 통해 팬 커버 내부의 난류 유동과 압력손실이 가장 작은 팬 커버 형상을 도출하였으며 개선된 냉각/통풍 시스템이 기존 냉각/통풍 시스템보다 6.5dB 감소된 것을 확인하였다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.5
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• pp.106-115
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• 1996

This study was carried out to provide fundamental data for reuse of resources and prevention of environmental pollution Actual states of environmental pollution by biological production facilities were investigated. Various pollution loads and quantity of wastes from greenhouse and animal housings estimated. In greenhouse contents of investigation were wastes of plastic cover, noise of heater and fan, air pollutant of heater, and wastes of soilless culture system, etc. In animal housings, those were actual state of livestock waste treatment and reuse, pollutant mass unit discharge, noise pollution, and malodorant, etc. The main pollutants discharged from greenhouses were wastes of plastic cover, rockwool, and waste fluid of nutrient solution. Developments of waste disposal methods for plastic cover and rockwool are required. And recycle technique of nutrient solution for soilless culture should be developed and propagated. With the buildup of legal control, pollutant mass discharged from livestock wastes are, on the decrease. The other side, reuse of livestock excreta increased. Most animal housings are located near the dwelling house. Malodorant and noise from animal housings have bad effects on the rural living conditions. So developments of integrated complex for small scale livestock farms are required.

• Land and Housing Review
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• v.11 no.3
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• pp.69-74
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• 2020

Since the design Standard for Energy Conservation in Building was implemented in 2008 for the first time, building elements such as window and door should satisfy the minimum criteria to apply for a building. Though its regulation does not cover the whole building yet, recent demand to reduce energy consumption in building sector grows rapidly year by year and also draws a lot of interest to ensure the whole building level. For example, a Zero energy building, one of low-energy buildings, requires a customized solution to resolve the air leakage issue to meet the standards in achieving the high level of air tightness. In this study, six non-residential buildings were tested by fan pressurization method to observe the air tightness of whole building to suggest the construction guideline for air tightness of low-energy building. Five out of six tested buildings showed 0.27 to 1.16 h^-1 of number of air changes except one community center. These buildings were carefully constructed not only for building planning but also for parts where there was a concern of air leakage, thereby securing high levels of air-tightness. The construction skills were developed as a checklist to manage and supervise the construction site. It is our suggestion to use this checklist at construction sites for ZEB with the high level of air-tightness.

• Korean Journal of Mathematics
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• v.26 no.1
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• pp.103-127
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• 2018

This paper is dedicated to studying some Hausdorff operators on the Heisenberg group ${\mathbb{H}}^n$. The sharp bounds on the strong-type weighted Lorentz spaces ${\Lambda}^p_u(w)$ and the weak-type weighted Lorentz spaces ${\Lambda}^{p,{\infty}}_u(w)$ are investigated. Especially, the results cover the classical power weighted space $L^{p,q}_{\alpha}$. The results are also extended to the product spaces ${\Lambda}^{p_1}_{u_1}(w_1){\times}{\Lambda}^{p_2}_{u_2}(w_2)$, especially for $L^{p_1,q_1}_{{\alpha}_1}{\times}L^{p_2,q_2}_{{\alpha}_2}$. Our proofs are quite different from those in previous documents since the duality principle, and some well-known inequalities concerning the weights are adopted. The results recover the existing results as well as we obtain new results in the new and old settings.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.173-179
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• 2002

There is a growing concert about energy efficiency at the present time. Even refrigerators can not be omitted from this issue. So the factors have been searched to decrease the consumption of electric power in refrigerators. It is possible to analyze the numerical data of the cover back machine and the change of condenser shape to find that they affect the consumption of electric powers by improving the fluid flow of within the interior of the refrigerator. As a result, the problems, fluid of the eddy and stationary of the existing refrigerator can be solved partly by the improved model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1461-1466
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• 2000

This paper investigates the noise reduction scheme in tractor cabin by using various steps of experiment. The experiments were performed in the field as well as in the lab to facilitate the detail test procedure. Some of the test results were compared with computational results. Several noise sources and paths were identified including the engine compartment (cooling fan and timing gear cover), hydraulic system and its components (hoses, tubes and there mount) and structural characteristics of the cab, window, mounting bracket and machine frame including steps. Throughout the several design changes, cab noise level was reduced from 80.2dBA to 74.8dBA.