• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 한국정밀공학회 2002년도 춘계학술대회 논문집
• /
• pp.561-564
• /
• 2002

With Rapid Prototyping system, the efficient packing in a fixed work volume reduces build time when multiple parts are built in a process. In this paper, an efficient and rapid packing algorithm is developed for SLS system that has cylindrical workspace. A genetic algorithm is implemented to place as many part as possible in a vat. For fast computation, a collision detection algorithm "k-DOPs Tree" is implemented.

• Management Science and Financial Engineering
• /
• 제19권1호
• /
• pp.25-28
• /
• 2013

Consider the inverse bin-packing number problem. Given a set of items and a prescribed number K of bins, the inverse bin-packing number problem, IBPN for short, is concerned with determining the minimum perturbation to the item-size vector so that all the items can be packed into K bins or less. It is known that this problem is NP-hard (Chung, 2012). In this paper, we investigate some special cases of IBPN that can be solved in polynomial time. We propose an optimal algorithm for solving the IBPN instances with two distinct item sizes and the instances with large items.

• Proceedings of the Korea Information Processing Society Conference
• /
• 한국정보처리학회 2009년도 춘계학술발표대회
• /
• pp.631-634
• /
• 2009

저궤도 관측위성의 개발 및 운영과정에서 위성의 내부 상태를 보다 면밀히 파악하고 분석하기 위하여 일반적인 telemetry 전송 주기인 초단위보다 짧은 주기로 데이터를 취합하여 지상으로 전송하기 위한 방법이 요구된다. 이를 위해 minor cycle 마다 sampling을 수행하는 telemetry packing 방법을 제안하고 구현한 바 있다. 여기서는 이전에 제안된 telemetry packing 방법을 확장하여 보다 다양한 요구사항을 충족시키기 위한 위성 소프트웨어의 설계에 대해 간략히 소개한다.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 한국건축시공학회 2020년도 봄 학술논문 발표대회
• /
• pp.94-95
• /
• 2020

This paper introduces the mix design and performance evaluation of Ultra-High Performance Concrete (UHPC). The concrete mixture is designed to achieve a densely compacted cementitious matrix via the modified Andreasen & Andersen particle packing model. The compressive strengths of UHPC designed by this method reached 154MPa. The relationship between packing theory and compressive strength of UHPC is discussed in this paper.

• Journal of the Korean Institute of Gas
• /
• 제11권1호
• /
• pp.34-39
• /
• 2007

In this paper, the FEM result has been presented for a sealing safety between a valve packing and a valve seat during a open and close operation in a LPG cylinder. The sealing operation of a LPG valve is completed when the valve packing in which is made by a nylon-66 polymer is to stop a LP gas flow, which flows out from the outlet of a brass pipe in a LPG cylinder. The contact sealing mechanism of the valve may be classified by a flat contact of an unused valve packing and a circular groove contact of an used valve packing in a current LPG valve. Based on the FEM and experimental investigations the sealing force, 4.9 MPa for a flat contact mode of the unused valve packing is a little high compared to that of the used valve packing, which shows a circular groove contact geometry against a valve seat. But these sealing pressures for two contact modes are very low compared to the ultimate strenath 83 MPa of the nylon-66 and this may be designed with a excess strength of the valve.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• 제28권9호
• /
• pp.1284-1296
• /
• 2004

In order to investigate effects of anisotropic fiber packing on stresses in composites, a Volume Integral Equation Method is applied to calculate the elastostatic field in an unbounded isotropic elastic medium containing multiple orthotropic inclusions subject to remote loading, and a Mixed Volume and Boundary Integral Equation Method is introduced for the solution of elastostatic problems in unbounded isotropic materials containing multiple anisotropic inclusions as well as one void under uniform remote loading. A detailed analysis of stress fields at the interface between the isotropic matrix and the central orthotropic inclusion is carried out for square, hexagonal and random packing of orthotropic cylindrical inclusions, respectively. Also, an analysis of stress fields at the interface between the isotropic matrix and the central orthotropic inclusion is carried out, when it is assumed that a void is replaced with one inclusion adjacent to the central inclusion of square, hexagonal and random packing of orthotropic cylindrical inclusions, respectively, due to manufacturing and/or service induced defects. The effects of random orthotropic fiber packing on stresses at the interface between the isotropic matrix and the central orthotropic inclusion are compared with the influences of square and hexagonal orthotropic fiber packing on stresses. Through the analysis of plane elastostatic problems in unbounded isotropic matrix with multiple orthotropic inclusions and one void, it will be established that these new methods are very accurate and effective for investigating effects of general anisotropic fiber packing on stresses in composites.

• Journal of environmental and Sanitary engineering
• /
• 제18권1호
• /
• pp.15-22
• /
• 2003

Treatability tests were conducted using EMC process to study the feasibility of applying this process as recycling-water treatment system in high density seawater aquaculture farm. To study the effect of organic and ammonia nitrogen loading on system performance, hydraulic retention time of reactor was reduced gradually from 12hr to 10min. The conclusions are can be summarized as follows. When the system HRT was reduced from 12hr to 10 min gradually, there was little noticeable change(reduction) in ammonia nitrogen removal efficiencies until 2hr of HRT, however, removal efficiencies were decreased dramatically when the system was operated under the HRT of less than 2hr. In case of organics(COD), there was no dramatic deterioration in removal efficiencies depending on HRT reduction. More than 90% of removal efficiencies were maintained successfully when the system was operated at the HRT of 10 min. In case of system performance depending on media packing ratio in reactor, there was little difference in each reactor performance depending on media packing ratio in reactor when the reactors were operated under the HRT of longer than 1hr, however, differences in reactor performances were considerably evident when the reactors were operated under the HRT of shorter than 1hr. That is, the more reactor was packed, the better reactor performed. When comparing reactor performance among 25%, 50%, 75% packed reactor, it can be judged that media packing ratio more than 50% plays no significant role in increasing reactor performance. For this reason, packing the media less than 50% is more reasonable way in view of economic. Such a tendency well agreed with the variation of ammonia-nitrogen removal efficiencies according to the media packing ratio in reactors at each HRT. Difference in effluent ammonia-nitrogen concentration between 50% media packing reactor and 75% media packing reactor was negligible. When comparing with the results of 25% packing reactor, difference was not so great.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• 제30권12호
• /
• pp.782-787
• /
• 2017

There is growing interest in power inductors in which metal soft magnetic powder and epoxy resin are combined. In this field, the process technology for increasing the packing density of magnetic particles in an injection molding process is very important. However, little research has been reported in this regard. In order to improve the packing density, we investigated and compared the sedimentation heights of pastes for three types of soft magnetic alloy powders as a function of the mixing ratios and the type of resin used. Experimental results showed that the packing density was the highest (71.74%) when the mixing ratio was 80 : 16 : 4 (Sendust : Fe-S : CIP) according to the particle size using an SE-4125 resin. In addition, the packing density was found to be inversely related to the layer separation distance. As a result, it was confirmed that the dispersion of solid particles in the paste was important for curing; however, the duration of the curing process can greatly affect the packing density of the final composite.

• Journal of the Korean Society for Railway
• /
• 제11권6호
• /
• pp.562-568
• /
• 2008

The modern logistics has tried not only to convert the conventional packing system into unit load system using pallet but also to enhance the fitness between packing facilities and transport modes. This is based on the goal to reduce total logistics cost by improving logistics efficiency. Since the packing unit can affect both loading rate and loading facilities, basic form of packing unit is very important to unit load system. The object of this study is to develop a new method for evaluating the effectiveness of standardized packing module. The new method is based on measure of effectiveness (MOE) which are identified by expert survey. This study has originality in that the collecting method for effectiveness of standardized packing module has not been developed up to now.

• Korean Journal of Mathematics
• /
• 제18권4호
• /
• pp.369-380
• /
• 2010

We give a criterion for vertex extremal length parabolicity of locally finite planar graphs, and use it to show that a disk triangulation graph is circle packing parabolic if and only if its immediate finer graphs are circle packing parabolic.