• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.212-219
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• 2002

The pipe with a long-neck flange is widely used in power plants, chemical plants, and shipbuilding companies. Now the pipe with a long-neck flange is manufactured by welding a thick flange to a pipe. But this long-neck flange pipe has some defects in the welding region such as unfitting and local thermal fatigue, which weaken the strength around the neck of the flange. Moreover, after welding the flange, the contacting surfaces of the flange have to be machined flat. So, that is uneconomical. Therefore, to solve the above problems of the long-neck flange pipe, a new process, which has no defects around the flange neck, is required. In this study, three forming processes are suggested to get an enhanced long-neck flange. First suggested process consists of conical forming and flange forming. Second and third suggested processes consist of the bulging of a long pipe locally heated by induction coils and the flange forming. The differences between second and third suggestions are the thickness and local heating area of the pipe. That is, the thickness of the initial pipe of third suggestion is larger than that of the final product, and the local heating area is smaller than that of second suggestion. These three suggestions for forming a long-neck flange are simulated by FE analyses with a commercial code DEFORM 2D. Especially, the theoretical result of FE analysis on the first suggestion for forming a long-neck flange is verified by the experiment with aluminum 6063 pipes. From the theoretical and experimental results, it is concluded that three suggested processes are very useful in order to manufacture the pipe with a long-neck flange without any defects.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.88-94
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• 2006

In this study, the dynamic impact analysis for the passenger air-bag(PAB) module has been carried out by using FEM to predict the dynamic characteristics of vehicle ride safety against head impact. The impact performance of vehicle air-bag is directly related to the design parameters of passenger air-bag module assembly, such as the tie bar bracket's width and thickness, respectively, However, the product's design of PAB module parameters are estimated through experimental trial and error according to the designer's experience, generally. Therefore, the dynamic analysis of head impact test of the passenger air-bag module assembly of automobile is needed to construct the analytical methodology At first, the FE models, which are consist of instrument panel, PAB Module, and head part, are combined to the whole module system. Then, impact analysis is carried out by the explicit solution procedure with assembled FE model. And the dynamic characteristics of the head impact are observed to prove the effectiveness of the proposed method by comparing with the experimental results. The better optimized impact performance characteristics is proposed by changing the tie bracket's width md thickness of module. The proposed approach of impact analysis will provides an efficient vehicle to improve the design quality and reduce the design period and cost. The results reported herein will provide a better understanding of the vehicle dynamic characteristics against head impact.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.224-230
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• 2011

For developing high performance fuel cell, peripheral devices and key components have to be studied in priority. In this study, centrifugal pump was studied for heat recovery. For PEM fuel cell system, a four-impeller centrifugal pump was designed, tested and compared with result of commercial product (IWAKI). In addition, effects of number of impeller were analyzed by CFD. The experiment and analysis were progressed in the same conditions. The results showed the quantitative difference under 30% between the numerical and the experimental pressure difference and mass flow rate.

• Journal of Astronomy and Space Sciences
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• v.32 no.2
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• pp.127-136
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• 2015

We present a by-product of our long term photometric monitoring of cataclysmic variables. 2MASS J18024395 +4003309 = VSX J180243.9 +400331 was discovered in the field of the intermediate polar V1323 Her observed using the Korean 1-m telescope located at Mt. Lemmon, USA. An analysis of the two-color VR CCD observations of this variable covers all the phase intervals for the first time. The light curves show this object can be classified as an Algol-type variable with tidally distorted components, and an asymmetry of the maxima (the O'Connell effect). The periodogram analysis confirms the cycle numbering of Andronov et al. (2012) and for the initial approximation, the ephemeris is used as follows: Min I. BJD = 2456074.4904+0.3348837E. For phenomenological modeling, we used the trigonometric polynomial approximation of statistically optimal degree, and a recent method "NAV" ("New Algol Variable") using local specific shapes for the eclipse. Methodological aspects and estimates of the physical parameters based on analysis of phenomenological parameters are presented. As results of our phenomenological model, we obtained for the inclination $i=90^{\circ}$, $M_1=0.745M_{\odot}$, $M_2=0.854M_{\odot}$, $M=M_1+M_2=1.599M_{\odot}$, the orbital separation $a=1.65{\cdot}10^9m=2.37R_{\odot}$ and relative radii $r_1=R_1/a=0.314$ and $r_2=R_2/a=0.360$. These estimates may be used as preliminary starting values for further modeling using extended physical models based on the Wilson & Devinney (1971) code and it's extensions

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.6
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• pp.547-558
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• 2008

Embedded system is tightly coupled with heterogeneous layers such as application, as kernel, device driver, HAL and hardware. Embedded system is customized for the specific purpose and hardware. In addition, the product cycle is so fast that software and hardware, which are developed by several vendors, are integrated together under unstable status. Therefore, there are lots of possibilities of faults in all layers. Because embedded software developers test their codes integrated with faulty layers, they cannot confirm 'whether testing of every aspects was completed, their code was failed, or integrated software/hardware has some problems'. In this paper, we propose an embedded software interface test method and a test tool called Justitia for detecting faults and tracing causes in the interface among heterogeneous layers. The proposed technique is an automated method which improves debugging upto professional testing using an emulator for helping developer.

• Journal of Distribution Research
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• v.3 no.1
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• pp.71-98
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• 1998

This study aimed to investigate how such retailers as department stores, large discount stores, book wholesalers, and clothing wholesalers used information technology for the QR strategy and whether the QR strategy had an effect on performance with a focus on the pipeline strategy. For this purpose, the QR strategy was divided into transaction efficiency, supplier partnership, and customer detail strategy. The differences in performance and information technology were analyzed according to the fit of the pipeline strategy, such as internal focus, supplier focus, and customer focus, the business strategy which were used by the retailers. And, an attempt was made to investigate whether performance was raised according to the level of adopting information technology. The results can be summarized as allows. First, the adaptive level of information technology had an effect on performance. But, seeing that the explanatory power of the regression analysis on the effect of the adaptive level of information technology on performance was shown to be very weak, it is judged that the level of QR information technology in the responding firms was very low compared to that of foreign firms. Second, information technology used by the retailers included universal product code, bar coding, customer database, and information utilities. It was shown that the group of firms seeking the transaction efficiency QR strategy and the internal focus pipeline strategy had the higher level of information technology than the retailers seeking other customer detail QR strategy and the customer focus pipeline strategy and the retailers with inconsistent strategy. This indicates that the firm seeking to raise its internal efficiency has a high level of using information technology. At the end of the paper, managerial implication and future research directions were discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9C
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• pp.860-870
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• 2005

In this paper we propose a new method to derive GRM(Generalized Reed-Muller) coefacients for each $2^{n}$ polarities using cell of karnaugh map(k-map). Generally, there are the serial and parallel method to derive GRM coefficients. As a serial method, Green method generates GRM coefncients using transform matrix. And as a parallel method, Besslich algorithm produces GRM coefficients of each polarity using the generated anteriorly. Green's method generates GRM coefficients for n-variable by calculating transform matrix for one-variable and n-times kronecker product this matrix. And Besslich's method generates GRM coefficients of each polarity in order of Grey-code. But those methods have disadvantages that the number of variable exceeding four makes transform matrix large and there are so many operation steps. In this paper, GRM coefficients is generated by producing cell [$f_{i}$] minimizing variable on k-map and operating this cell [$f_{i}$] and transform matrix for one-variable. So, we can generate GRM coefficients of all polarities easily by using the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2B
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• pp.296-301
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• 2010

Radio frequency identification(RFID) system can identify an object using wireless transmission. RFID applications are numerous and far reaching. The most interesting and widely used applications are supply chain management for companies. Currently, RFID tags must be detached or killed for security and privacy reasons when tagged objects are purchased. In this paper, we present a new architecture that transfers information about products from the electronic product code information services (EPCIS) server of a company to an individual's personal purchases management (PPM) server when products with RFID codes are sold. It solves the security and privacy issues without detaching the tag. Moreover, the PPM server described in this paper allows customers to handle the expiration dates, updates, location management, and group management of products.

• The KIPS Transactions:PartD
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• v.17D no.3
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• pp.193-202
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• 2010

Recently, there have been several researches on automatic object identification and distributed computing technology to realize a ubiquitous computing environment. Radio Frequency IDentification (RFID) technology has been applied to many business areas to simplify complex processes and gain important benefits. To derive real benefits from RFID, the system must rapidly implement functions to process a large quantity of event data generated by the RFID operations and should be configured dynamically for changing businesses. Consequently, developers are forced to implement systems to derive meaningful high-level events from simple RFID events and bind them to various business processes. Although applications could directly consume and act on RFID events, extracting the business rules from the business logic leads to better decoupling of the system, which consequentially increases maintainability. In this paper, we describe an RFID business aware framework for business processes in the Electronic Product Code (EPC) Network. This framework is proposed for developing business applications using business services. The term "business services" refers to generated events that can be used in business applications without additional data collection and processing. The framework provides business rules related to data collection, processing, and management, and supports the rapid development and easy maintenance of business applications based on business services.

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.25-30
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• 2009

The present study deals with numerical investigation for smoke behavior in rescue station by using the commercial CFD code (FLUENT Ver 6.3). With the use of the MVHS(Modify Volumetric Heat Source) model modified from the original VHS(Volumetric Heat Source) model, a 10 MW mode was adopted for simulation and the MVHS model can describe the generation of product and the oxygen consumption at the stoichiometric state. In addition, the present simulation includes the species conservation equations for the materialization of heat source and the estimation of smoke movement. From the results, the smoke flows are moving along the ceiling because of thermal buoyancy force and as time goes, the smoke gradually moves downward at the vicinity of the entrance. Moreover, without using ventilation, it is found that the smoke flows no longer spread across the cross-passages because the pressure in the non-accident tunnel is higher than that in the accident tunnel.