• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.8
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• pp.1468-1484
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• 1992

In the present paper forward projection is proposed as a new approach to determine the preform shape in rib-web type forging. In the forward projection technique an optimal billet is determined by applying some mathematical relationship between geometrical trials in the initial billet shape and the final products. In forward projection a volume difference between the desired product shape and the final computed shape obtained by the rigid-plastic finite element method is used as a measure of incomplete filling of working material in the die. At first linear inter-/extrapolation is employed to find a proper trial shape for the initial billet and the method is successfully applied to some cases of different aspect ratios of the initial billet. However, when the initial guesses are not sufficiently near the optimal value linear inter-/extrapolation does not render complete die filling. For more general application, a fuzzy system is used in the forward projection technique in order to determine the initial billet shape for rib-web type forging. It has been thus shown that the fuzzy system is more reliable for the preform design in the rib-web type forging process.

• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.42-47
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• 2012

In this paper, alternative natural refrigerant R290(Propane), R600(Butane), R717(Ammonia), R1270(Propylene) for freon refrigerant R22 were used working fluids for 2-stage compression and 1-stage expansion refrigeration system. The operating parameters considered in this study included evaporation temperature, condensation temperature, subcooling degree, superheating degree, mass flow rate ratio of inter-cooler. The main results were summarized as follows : The COP of 2-stage compression and 1-stage expansion refrigeration system increases with the increasing subcooling degree and mass flow rate ration of inter-cooler, but decreases with the increasing evaporating temperature, condensing temperature and superheating degree. Therefore, subcooling degree, mass flow rate ratio of inter-cooler of 2-stage compression and 1-stage expansion refrigeration system using natural refrigerants have an effect on COP of this system. The COP of natural refrigerants was higher than the COP of freon R22 in this study, so points to be considered are the security, the attached facilities for natural refrigerants than COP.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.219-226
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• 2020

The container terminal operators established a re-marshalling plan to reduce the loading operation time and the release operation time. Re-marshalling is to rearrange the containers in the container yard to the advantageous position to shorten the working time using the spare time of the automated yard crane. This study assumed the automated container terminal with a perpendicular layout and deals with the inter-bay re-marshalling planning problem in a yard block. The inter-bay re-marshalling plan determines the container to be moved, the location to be relocated, and the sequence of relocation operations. This study presents a mixed integer programming model that simultaneously determines the storage location and the operation sequence while satisfying the spatial availability during the re-marshalling. Numerical experiments are conducted to understand re-marshalling operation using a beam search method.

• Journal of Korean Library and Information Science Society
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• v.2
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• pp.1-21
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• 1975

Thc purposc of this .study is for ri~aking a model of building a library collcction dcnizn~cd on th.3 curriculum through thc inter-comparison of 15 standards for collcgc ant1 anivcrsily libraries in 5 countries (U. S. A.. Great Ikitain, Canada, Japan, and Icorca) Thc rcsult of thcscl colnpsrisons is as follow.. (1) Qu;~nlitalivc scope: of thc cull(:ction: (r/ Standards for a minimal collcction arc presented to about 100,000 vols (20-30 vols per student) for a ncw university and about 40,000 vols (40 vols pcr studcnt) for a nrnr collcge. $)$ Standards for a working collcction arc prescnted to 70-80 vols per student for a univer:aity and 50-60 vols per student for a college. $$ Standard for an intcnsive rescc~rch collcction is presented to morc than 100 vols p::r studcnt. (2) Stop: of the annual incrc;lsc cf thc collection: (i: Standard for a minimal collcction is ~~rescntcdto 1.4-2 vols per studcnt. $$ Standard for an intensive rrscarch or working collection is pcrsented to 4-5 vols pcr studcnt. (3) Scope of thc anni.1a1 budgetary standards: In Grcat I3ritain and U.S. A.. th-re aro assigned to 1 . 5 ~ 2 % of the collcge and university cxpcnditurr for books. $,$ In our country, it is prcscntcd to 3.5% of thc collcge and university expenditure for books, whcn my calculating by thc various factor analysis.

• Journal of the Korean Society of School Health
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• v.30 no.3
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• pp.181-193
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• 2017

Purpose: This is a qualitative descriptive study with the purpose of identifyng the health problems and related factors of socially vulnerable school-age children in Seoul, South Korea. Methods: Two focus group interviews and two individual interviews were conducted with eleven participants. They were two class teachers, three school nurses and two daycare teachers working at elementary schools and three social workers and a welfare worker working at community childcare centers. Data were analyzed using qualitative content analysis. Results: The identified psychosocial problems were 'distracting and excessive behavior', 'depression and helplessness,' 'aggression and violent behaviors', and 'internet overdependence'. The revealed physical health problems were 'poor hygiene', 'obesity', and 'gastrointestinal problems'. In addition, the fact that physical and psychosocial problems are closely inter-linked was reaffirmed through practical examples. Meanwhile, socioeconomic, family environmental, social experiential and individual factors were found to affect children's health. Relationships within a family or a peer group and healthy lifestyle were considered critical issues to deal with in order to improve the childrens' health status. Conclusion: It was proved that socially vulnerable school-age children have various physical and mental health problems due to multiple factors. Therefore, it is required to design nursing approaches that help them achieve optimal health status.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.6
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• pp.151-158
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• 2022

Even after three decades of economic reforms, India's labor market is characterized by stark inter-gender differences in terms of both participation rate and working time. Identification of the causes is necessary to remove the disparity and unequal sharing of economic opportunities to make way for women's empowerment. This research attempts in that direction, examining the prevalence of these inequities in rural areas of North-East Indian states using unit-level data from the 2017-18 Periodic Labour Force Survey (PLFS). The methodology for the estimation here is based on Blinder- Oaxaca decomposition method after correcting for sample bias forwarded by Heckman. The analysis shows that in both labor force participation and the wage gap, the females in the region lag behind their male counterparts by a huge margin. Further, the analysis shows that one of the main factors leading to the difference is the disparities in human capital assets. On top of female educational enrollment being low, there is also a huge lack of higher educational attainment, while males have accomplished much better in both the parameters. Moreover, the presence of social stigma against women working and discrimination put the female labor outcomes in a gloomy state.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.1017-1024
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• 2004

In this paper, we propose the progressed interworking method between H.323 and SlP, then explain the improved property. The VolP(Voice over Internet Protocol) technology which is able to use a voice service through internet is more cheaper then existing telephone charges, and is easil)· accept the various of multimedia services from internet. Previous connectionmethod of VoIP used H.323 protocol, but it is very complex to connection establishment. so, the SIP(Session Initiation Protocol) protocol that propose in SIP-Working Group is in use recently. Therefore, we need new interworking methodology between H.323 and SIP Products. In this thesis, the progress interworking method between H.323 and SIP are Propose, then interpret unnecessary packet delay for call setup and improved feature of message exchange.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.5
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• pp.421-427
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• 2008

A robot crane truck is developed by the Bridge Inspection Robot Development Interface(BRIDI) for an automated and/or teleoperated bridge inspection. This crane truck looks similar to the conventional bucket crane, but is much smaller in size and light-weight. At the end of the telescoping boom which is 12m long, a robot platform is mounted which allows the operator to scan the bridge structure under the deck trough the camera. Boom vibration induced by wind and deck movement can cause serious problems in this scanning system. This paper presents a control system to mitigate such vibration of the robot boom. In the proposed control system, an actuator is installed at the end of the working boom. This control system is studied using a mathematical model analysis with LQ control algorithm and a scaled model test in the laboratory. The study indicates that the proposed system is efficient for the vibration control of the robot booms, thereby demonstrating its immediate applicability in the field.

• Journal of Distribution Science
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• v.14 no.6
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• pp.107-118
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• 2016

Purpose - Over 90% of Domestic logistics industry is small enterprise and they are experiencing growth stagnation due to price-based competition structure rather than constructing logistics service of high added value. In order to get over this situation and pursue the development of logistics industry, strengthening its competitiveness, through inter-enterprise cooperative network build-up, would be a key alternative. Therefore, in this study, an index for measuring inter-enterprise cooperation level of Joint logistics business will be developed as a typical collaborative business model in logistics industry. Moreover, a strengthening competitiveness method suggests a developmental step and a key management index to mature in logistics industry. Research Design, Data, Methodology - This study is an index development research for measuring inter-enterprise cooperation level of logistics industry. Such a level was measured by performing a survey by targeting enterprises that participated in Joint logistics business. The targeting enterprises are typical cooperative models in logistics industry. Measurement items were developed which were based on the presented items in existing research. Question items were composed of selection type questions as answering Yes/No. They measures implementation status of corporate activity and detailed activity items measuring qualitative level. Total samples were based on 116 enterprise samples including 90 logistics enterprises and 26 shippers. In addition, by evaluating the importance for Joint logistics business recognition with personnel working level, the weight of measuring variable was extracted. This study has built an assessment tools (LPCI) on Joint logistics business cooperation level in a situation where there are no previous studies on joint logistics business, this study is meaningful for other studies. Results - As a result of analyzing LPCI presented in this study, the score of logistics enterprise was represented as 59.9 points based on full score of 100 points and that of shippers as 47.2 points and cooperation level among enterprises participated in Joint logistics business was revealed to be very low. In particular, as a result of measuring the importance between logistics enterprise and shippers, the difference by each measurement standard was represented among those enterprises. This difference is considered to be a key factor that cooperative operational conformity between logistics enterprises and shippers is represented to be low. Conclusions - As most joint logistics business, being promoted at present, is sharing facility and information with joint logistics business, it is hard to find such a joint logistics business in reality based on cooperative business model in main cooperation agents. Therefore, competitiveness of logistics industry could be strengthened by promoting joint logistics business based on their mutual cooperation among enterprises. In other words, it is to secure sustainable competitiveness of joint logistics business together with creation of new market by inter-enterprise cooperation based on integration of basic logistics business.

• Computational Structural Engineering
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• v.6 no.4
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• pp.83-88
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• 1993

A time-discontinuous Galerkin method based upon using a finite element formulation in time has evolved. This method, working from the differential equation viewpoint, is different from those which have been generally used. They admit discontinuities with respect to the time variable at each time step. In particular, the elements can be chosen arbitrarily at each time step with no connection with the elements corresponding to the previous step. Interpolation functions and weighting functions are taken to be discontinuous across inter-element boundaries. These methods lead to a unconditional stable higher-order accurate ordinary differential equation solver.