• 한국정밀공학회지
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• 제19권7호
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• pp.171-179
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• 2002

STEP-NC is the next generation CNC controller taking STEP-based data model as the interface scheme (or language) between CAM and CNC, and carrying out various intelligent functions. At the moment, efforts are being made worldwide to establish international standard for the new interface scheme formalized as ISO14649. As the new language is being established, increasing attention is being paid to the development of the new CNC. Korea STEP-NC is an integrated STEP-NC system taking ISO 14649 as an input, and carrying out various intelligent functions. It is composed of 5 modules: 1) Shop Floor Programming System (PosSFP), 2) Tool Path Generator (PosTPG), 3) Tool Path Viewer (PosTPV), 4) Man Machine Interface (PosMMI), and 5) CNC Kernel (PosCNC). Distinguished from other prototypes (of Europe and USA), the Korea STEP-NC is top-down designed, and bottom-up implemented comprehensively incorporating all the crucial components for realizing the full benefit of STEP-NC paradigm, without using any existing commercial CAD/CAM systems and CNC kernels. The Korea STEP-NC prototype was successfully demonstrated and evaluated in the ISO conventions Together with prototypes of Europe and USA, Korea STEP-NC will be used as a reference system fur the Triangular Conformance Test to be jointly carried out by ISO TC184 SC1, SC4, and IMS Project.

• 한국화재소방학회논문지
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• 제34권4호
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• pp.101-106
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• 2020

자체 제작된 니들 플레임을 이용하여 바닥재를 수직 연소시켰을 때의 화염의 성장 특성 및 탄화 패턴을 해석하였다. PVC 장판은 난연성이 있는 것으로 확인되었고, 직사 화염을 받은 곳은 안쪽으로 수축되는 패턴을 나타냈다. 수직 연소가 진행되면 하부에 망울 형태의 고형화가 발생하며, 그을음은 상부로 성장하는 패턴이 형성된다. 강화마루는 난연성이 없는 것으로 확인되었으며, 상부 표면인 라미네이트층의 소실과 불규칙적인 박리가 형성되는 것을 알 수 있다. 좌측면과 우측면의 탄화의 범위는 대칭적 구조를 나타내는 것으로 해석된다. 강화마루와 마찬가지로 카펫은 수직 연소 실험에서 난연성이 없는 것이 확인되었다. 카펫에 축열이 형성되면 화염은 상승기류를 형성하고, 주변에 가연성 물질이 있을 때 화염의 확산은 더욱 촉진하는 것을 알 수 있었다. 직사화염을 받은 카펫 표면의 탄화 패턴은 표면이 용융되어 흘러내렸을 뿐만 아니라 작은 구멍이 다수 발생되는 것을 알 수 있다.

• 대한기계학회논문집B
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• 제24권5호
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• pp.632-639
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• 2000

Conjugate heat transfer from a heat generating module ($31{\times}31{\times}7mm^3$) bonded through the module support on the floor of a parallel-plate channel(20mm high, 400mm wide, and 800mm long) to mixed convective air flow(0.2${\sim}$0.9m/s) is studied experimentally. The input power to the module is changed in a range 1.0${\sim}$4.5W, the floor thickness 0.2${\sim}$5mm, and the thermal resistance of module support, Rc:=0.06, 1.03 and 82.0K/W. Thermal conductance(Uc) of the board and convective thermal conductance($U_A$) from the module were derived, and the effect of V; Rc and t on Uc was investigated. It is found that the conjugate conductance (Uc) and the conductive heat transfer ratio ($Q_B$/Q) depend on the thermal resistance of the module support, the air velocity and the board thickness. The change of the module support resistance and the board thickness helps to elucidate the relative significance of heat transfer paths through the module support, the board, and from the board surface to the air. Additional information is investigated about the dependence of the heat transfer rate on the mixed convection parameter.

• 한국지진공학회논문집
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• 제24권5호
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• pp.233-241
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• 2020

This paper is to investigate the retrofitting effect for a non-seismic reinforced concrete frame strengthened by perimeter steel moment frames with indirect integrity, which ameliorates the problems of the direct integrity method. To achieve this, first, full-scale tests were conducted to address the structural behavior of a two-story non-seismic reinforced concrete frame and a strengthened frame. The non-seismic frame showed a maximum strength of 185 kN because the flexural-shear failure at the bottom end of columns on the first floor was governed, and shear cracks were concentrated at the beam-column joints on the second floor. The strengthened frame possessed a maximum strength of 338 kN, which is more than 1.8 times that of the non-seismic specimen. A considerable decrease in the quantity of cracks for the strengthened frame was observed compared with the non-seismic frame, while there was the obvious appearance of the failure pattern due to the shear crack. The lateral-resisting capacity for the non-seismic bare frame and the strengthened frame may be determined per the specified shear strength of the reinforced columns in accordance with the distance to a critical section. The effective depth of the column may be referred to as the longitudinal length from the border between the column and the foundation. The lateral-resisting capacity for the non-seismic bare frame and the strengthened frame may be reasonably determined per the specified shear strength of the reinforced columns in accordance with the distance to a critical section. The effective depth of the column may be referred to as the longitudinal length from the border between the column and the foundation. The proposed method had an error of about 2.2% for the non-seismic details and about 4.4% for the strengthened frame based on the closed results versus the experimental results.

• 한국해양공학회지
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• 제31권4호
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• pp.308-314
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• 2017

The purpose of this study was to investigate the sea floor using a seismic profiler in the northern part of Chagwi-do of Jeju Island in order to select the optimal location for the 60-m-class berth of a sea test bed for wave energy converters and provide basic environmental data for designing a suction anchor. The echo types of the seismic profiles were classified based on the study of Kim et al. (2016a), and the location for installing the suction anchor was selected based on a sediment thickness of more than 10 m. The physical properties of the surface sediments were determined by analyzing the sediment samples obtained from 16 grab sample points. Based on the investigation and analysis, we proposed a survey area in the North-Eastern sea as an optimum location for the 60-m-class berth where the suction anchor could be installed.

• Coupled systems mechanics
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• 제11권6호
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• pp.557-586
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• 2022

In spite of extensive testing of the individual shear wall and the coupling beam (CB), numerical and experimental researches on the seismic behavior of CSW are insufficient. As far as we know, no previous research has investigated the affectations of position of CB regarding to the slab level (SL). So, the investigation aims to enhance an overarching framework to examine the consequence of connection positions between CB and SL. And, three cases have been created. One is composed of the floor slab (FS) at the top of the CB (FSTCB); the second is created with the FS within the panel depth (FSWCB), and the third is employed with the FS at the bottom of the CB (FSLCB). And, FEA is used to demonstrate the consequences of various CB positions with regard to the SL. Furthermore, the main measurements of structure response that have been investigated are deformation, shear, and moment in a coupled beam. Additionally, wall elements are used to simulate CB. In addition, ABAQUS software was used to figure out the strain distribution, shear stress for four stories to further understand the implications of slab position cases on the coupled beam rigidity. Overall, the findings show that the position of the rigid linkage among the CB and the FS can affect the behavior of the structures under seismic loads. For all structural heights (4, 8, 12 stories), the straining actions in FSWCB and FSLCB were less than those in FSTCB. And, the increases in displacement time history response for FSWCB are around 16.1-81.8%, 31.4-34.7%, and 17.5% of FSTCB.

• 한국음향학회지
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• 제27권6호
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• pp.286-295
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• 2008

수중에서의 통신은 해수면과 해저면 등에 의한 신호의 반사가 생겨 다중경로 현상이 발생한다. 이러한 다중경로의 영향으로 신호는 왜곡되고 원활한 수신을 방해하게 된다. 이에 각종 통신시스템에서 적용되고 있는 여러 가지 채널 부호 방법을 모델링된 수중통신채널에 적용하여 그 성능을 확인하였다. 그 결과 다중경로에 의한 오류의 특성은 랜덤오류의 특성을 가지기 때문에 인터리버의 효과는 거의 볼 수 가 없으며, 수중채널에서 다중경로에 의해 야기된 오류마루 현상을 극복하기 위해서는 LDPC 부호와 같은 강력한 오류 정정 부호가 요구되며, RS 부호등을 연접하여 사용할 경우 더욱 우수한 성능을 보이는 것을 확인할 수 있었다.

• 가정과삶의질연구
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• 제24권5호
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• pp.89-99
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• 2006

The purpose of this study was to devise guidelines for the kitchen workspace of the aged by examining current usage. To achieve this objective, surveys were conducted and measurement were taken between June 15 and lune 30, 2005. The data were gathered from 50 women over 65- years-old who live in the downtown and suburbs of Seoul, Korea. The collected data were processed using SPSS 12.0 for Microsoft Windows and resulted in the following conclusions: The kitchen for the aged needs to be laid out in ㄱ-shape and the refrigerator needs to be positioned prominently. The height of the work counter is relative to the user's height (${\times}0.49{\sim}056$). and the length varies depending on the available space of the house and the type of work counter needed: however it was found that it should be at least 270cm Concerning the depth of the work counter, the standard sizes (60cm) currently on the market did not cause any inconvenience. It was found that the sink must be designed to allow for some space at the bottom so as to ensure comfortable sedentary work. Also, an electrical oven was preferred over a gas-fuelled one. Finally, the height of the upper cabinet should be relative to the user's height at ${\times}0.85{\sim}1.0$ from the floor to the bottom of the cabinet.

• 한국해양학회지
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• 제28권4호
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• pp.259-271
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• 1993

한반도 주변해역 대륙붕의 표층퇴적물 연구 결과 대륙붕 퇴적물은 크게 니질퇴적 상과 사질퇴적상으로 대표되는 전형적인 쌍빈도 입도특성을 나타낸다. 외대륙붕지역에 넓게 분포하는 사질 및 역질퇴적물은 지난 빙하기 해수면 하강 당시 집적된 잔류 퇴적 물로 해석되며, 내대륙붕 해저에 분포하는 세립한 지질퇴적물은 현재의 퇴적환경에서 공급, 운반, 집적된 현생퇴적물도 해석된다. 이들 세립물질은 강한조석전선 및 연안전 선에 의하여 외양쪽 확산이 크게 제한되며, 한반도 연안에 따라 서해로부터 남해를 거 쳐 동쪽방향으로 운반되는 것으로 해석된다. 그러나 동해의 우포분지에 분포하는 암회 색의 니질퇴적물은 잔류성 퇴적물로 여겨진다. 중간대륙붕 지역에는 현생의 세립물질 이 사립의 잔류퇴적물과 혼합된 혼합성퇴적물이 분포한다. 또한 잔류퇴적물의 일부는 현재의 해양환경조건에서 지속적으로 재동된 Palimpset 퇴적물로 해석된다.

• 한국지열·수열에너지학회논문집
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• 제12권4호
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• pp.40-46
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• 2016

In order to improve air quality of indoor environment, studies of the underfloor air distribution (UFAD) system for application in buildings are actively in progress based on temperature and air flow distribution. However, although the age of air is the major evaluation parameter, there has been very little study on this parameter for the UFAD system. In this study, we investigated the age of air to reach the air diffuser, which is installed at the bottom of the interior by the UFAD system. Computational fluid dynamics simulations showed no regular pattern to the maximum value of the age of air in accordance with air flow rate and the velocity at air diffuser. These factors can be deduced from air movement by considering that air emitted from air conditioners was rotated according to the bottom shape of the floor, and then, the age of air in the rotation center was increased. The average age of air of internal interior was reduced considerably as the flow velocity at the underfloor air diffuser was increased from 0.5 m/s to 1.0 m/s However, the age of air was not substantially affected with change in the air volume. Moreover, when the flow velocity at the underfloor air diffuser was higher than 1.0 m/s, the age of air showed no significant difference with change in air volume or height of measurement. These results imply that indoor air quality is more substantially influenced by flow velocity than air volume, and the appropriate flow velocity is 1 m/s or more.