• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.169-177
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• 2012

This paper considers the explicit guidance algorithm to determine the closed-loop guidance law applicable to upper stages of a given space launch vehicle. It has the advantage of very simple forms derived from the flat earth assumption, which is appropriate for its on-board application. However the simple time-to-go prediction equation produces the degraded guidance performance of the launcher because of its inaccuracy. To overcome the problem, the elaborate prediction equations, which have been employed in Saturn and H-II, are attempted here. Finally, the simulation results show that the simple guidance approach requires the more accurate time-to-go prediction and gravity integrals for its broad application.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.3
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• pp.243-250
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• 2009

The adjoint variable method can reduce computation time and save computer resources because it can selectively provide the sensitivity information for the positions that designers wish to measure. However, the adjoint variable method commonly employs exact analytical differentiation with respect to the design variables. It can be cumbersome to precisely differentiate every given type of finite element. This trouble can be overcome only if the numerical differentiation scheme can replace this exact manner of differentiation. But, the numerical differentiation scheme causes of severe inaccuracy due to the perturbation size dilemma. For assuring the accurate sensitivity without any dependency of perturbation size, this paper employs a complex variable that has been mainly used for computational fluid dynamics problems. The adjoint variable method combined with complex variables is applied to obtain the shape and size sensitivity for structural optimization. Numerical examples demonstrate that the proposed method can predict stable sensitivity results and that its accuracy is remarkably superior to traditional sensitivity evaluation methods.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.53
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• pp.101-133
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• 2012

The paper aims to analyse the obligations and Responsibilities of shipper in the Rotterdam Rules. The Rotterdam Rules, has underlying intention that it will provide uniform law for the international carriage of goods by sea. It is highly expected that the Rotterdam Rules will create the new international legal regime replacing Hague-Visby Rules and Hamburg Rules. Rotterdam Rules provide the obligations and responsibilities of shipper in express. The shippers obliged to provide, (a) duty as to the condition in which the cargo has to be delivered to the carrier, (b) cooperation of the shipper and the carrier in providing information and instruction, and (c) shipper's obligation to provide information, instructions and documents. The shipper is liable for loss or damage sustained by the carrier if the carrier proves that such loss or damages was caused by a breach of the shipper's obligations. However, the shipper is relieved of all or part of its liability if the cause or one of the causes of the loss or damage is not attributable to its fault or to the fault. But, the shipper shall indemnify the carrier against loss or damage resulting from the inaccuracy of such information. Rotterdam Rules is providing rather concrete as to the shipper's responsibilities and burden of proof in separate chapter. The question is whether such burden of proof of the fault should be imposed to the shipper.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.355-365
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• 1998

The purpose of this study is to evaluate the accuracy of four elastomeric interocclusal recording materials and the weight change according to different storage period (24 hours, 48hours, 7days) and different conditions (dry, wet). The techniques for establishing the intercuspal position were centic occlusion interocclusal record with four elastomeric interocclusal recording materials (Ramitec, Stat-BR, Blu-Mousse, Regisil) (experimental groups) and location of the cast in a position of maximum in-terdigitation using tactile and visual method(control group). To evaluate the accuracy of four elastomeric interocclusal recording materials, the quality of contacts between the mounted casts was compared with the results of an occlusal examination of the same subjects. The results were as follows : 1. The most accurate method of articulating study casts at the intercuspal position was by hand articulation and no significant differences in accuracy were observerd among the experimental groups. 2. In case of interocclusal records storaged in dry sealed plastic box, no significant differences in accuracy were observed among the experimental groups. 3. In case of interocclusal records storaged in water, there was significant inaccuracy in Ramitec group. 4. The biggest weight change was observed in Ramitec group in all storage conditions

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.837-842
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• 2000

In the coiling process of helical steam generator tubes of integral reactor SMART, a considerable amount of spring back, which induces dimensional inaccuracy and difficulty in fabrication, has been arised. In this research, an analytical model was derived to evaluate the amount of the spring back for steam generator tubes. The model was developed on the basis of beam theory and elastic-perfectly plastic material property. This model was extended to consider the effect of plastic hardening and the effect of the tensile force on the spring back phenomena. Parametric studies were performed for various design variables of steam generator tubes in order to minimize the spring back in the design stage. A sensitivity analysis has shown that the low yield strength, the high elastic modulus, the small helix diameter, and the large tube diameter result in a small amount of the spring back. The amount of the spring back can be controlled by the selection of adequate design values in the basic design stage and reduced to an allowable limit by the application of the tensile force to the tube during the coiling process.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.2
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• pp.173-189
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• 1995

purpose of this study is to analyze the various phenomenon related to the subjectivism of aesthetic value for dress, which is impossible to describe with only functionalism, practically and objectivism of aesthetic value for dress based on Karl Rosencrantz\ulcorners theory of the Aesthetics of ugliness from the middle of 1980's to present. In other words, the ugliness had been selected and erected as the opposite meaning of beauty to head toward ultimate beauty, and clarify that ultimate beauty is achieved through the combination of beauty is achieved through the combination of beauty and ugliness. First, the ugliness and Rosencrantz\ulcorners theory of the Aesthetics of Ugliness had been examined theoretically in the aspect of the subjectivism of aesthetic value for dress and aesthetic category. The relationship between the artistic styles related to ugliness, such as Avant-garde, Primitivism of Expressionism, Grotesque, Decadence, Kitsch, Pastich\ulcornerParody, from the late 19c to present, and the dresses representing the ugly look such as Cyber Punk, Exotic look, Detester, Grunge, Hip-hop, etc, of 1990's had been studied by using photographic materials. In this study, the basic concepts of ugliness, including formlessness, inaccuracy and deformation, formed by K. Rosencrantz had been used to reveal the interaction between modem costume and the theory of ugliness.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.10
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• pp.968-974
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• 2006

We are moving into the era of ubiquitous computing. Ubiquitous Sensor Network (USN) is a base of such computing paradigm, where recognizing the identification and the position of objects is important. For the object identification, RFID tags are commonly used. For the object positioning, use of sensors such as laser and ultrasonic scanners is popular. Recently, there have been a few attempts to apply RFID technology in robot localization by replacing the sensors with RFID readers to achieve simpler and unified USN settings. However, RFID does not provide enough sensing accuracy for some USN applications such as robot navigation, mainly because of its inaccuracy in distance measurements. In this paper, we describe our approach on achieving accurate navigation using RFID. We solely rely on RFID mechanism for the localization by providing coordinate information through RFID tag installed floors. With the accurate positional information stored in the RFID tag, we complement coordinate errors accumulated during the wheel based robot navigation. We especially focus on how to distribute RFID tags (tag pattern) and how many to place (tag granularity) on the RFID tag-floor. To determine efficient tag granularities and tag patterns, we developed a simulation program. We define the error in navigation and use it to compare the effectiveness of the navigation. We analyze the simulation results to determine the efficient granularities and tag arrangement patterns that can improve the effectiveness of RFID navigation in general.

• Transactions of Materials Processing
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• v.22 no.8
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• pp.477-485
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• 2013

This paper aims to evaluate quantitatively the springback characteristics that evolve in the sheet metal forming of an S-rail in order to understand the reasons of shape inaccuracy and to find a remedy. The geometrical springback is classified into six modes: angle change of punch and die shoulders, wall curl, ridge curl, section twist, and axial twist. The measuring method for each springback mode is suggested and quantitative measurements were made to determine the tendency towards shape accuracy. Forming experiments were conducted with four types of steel sheets that have different tensile strengths, which were 340MPa, 440MPa, 590MPa and 780MPa, in order to evaluate the effect of the tensile strength and the bead shape on the springback behavior. Springback tendencies show that they are greatly affected by the tensile strength of the sheet and the shape of the tools. Almost all springback modes except the section twist and the axial twist show a linearly increasing trend as the tensile strength of the sheet increases. The results can be used as basic data for design and for compensation of the press die geometry when forming high strength steels which exhibit large amounts of springback.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.515-528
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• 2012

The aim of this article is to provide a study on the issue of inventory inaccuracy and to show the manner in which RFID technology can improve the inventory management performance. The objective of inventory control is to monitor the stock flow of merchandises in order to understand the operating profit and loss. A proper mechanism of inventory control could be made to help the profitability. As RFID is applied to inventory control, it can improve efficiency, enhance accuracy and achieve security. In this paper, we introduce the evolution of different mechanisms of inventory control with RFID system-counting method, collect-all method, and continuous monitoring method. As for improving the accuracy of inventory check during business hours, continuous monitoring is the solution. We introduce the infrastructure of the RFID inventory management system based on M2M architecture can make the inventory be efficiently monitored with instant warnings.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.5
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• pp.45-50
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• 2011

Compression pressure of individual cylinder and valve timing have big influence on combustion pressure, indicated mean effective pressure (IMEP), emission, vibration, combustion noise and many other combustion parameters. Conventional method, however, to check compression pressure uniformity is done by mechanical pressure gage and valve timing is checked manually. This conventional method causes inaccuracy of cylinder pressure measurement because of different cranking speed results from battery status and temperature. Also to check valve timing, related FEAD parts should be disassembled and timing mark should be checked. This study describes and suggests new methodology to measure compression pressure by analysis of start motor current and to check valve timing by cylinder pressure with high accuracy. Results, it is found that detection of bulky as well as small leaky cylinder is possible by cranking motor current analysis and wrong valve timing can be detected by cylinder pressure analysis and cam and crank sensor signal.