• Journal of the Microelectronics and Packaging Society
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• v.26 no.2
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• pp.31-43
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• 2019

In this study, polymer elastic bumps were fabricated for the flexible electronic package flip chip bonding and the viscoelastic and viscoplastic behavior of the polymer elastic bumps according to the temperature and load were analyzed using FEM and experiments. The polymer elastic bump is easy to deform by the bonding load, and it is confirmed that the bump height flatness problem is easily compensated and the stress concentration on thin chip is reduced remarkably. We also develop a spiral cap type and spoke cap type polymer elastic bump of $200{\mu}m$ diameter to complement Au metal cap crack phenomenon caused by excessive deformation of polymer elastic bump. The proposed polymer elastic bumps could reduce stress of metal wiring during bump deformation compared to metal cap bump, which is completely covered with metal wiring because the metal wiring on these bumps is partially patterned and easily deformable pattern. The spoke cap bump shows the lowest stress concentration in the metal wiring while maintaining the low contact resistance because the contact area between bump and pad was wider than that of the spiral cap bump.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.21-21
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• 2000

• Journal of Aerospace System Engineering
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• v.4 no.2
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• pp.1-9
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• 2010

An airless tire has advantages over the conventional pneumatic tire in terms of flat proof and maintenance free. According to the recently disclosed inventions on the airless tire, non-pneumatic tire (NPT) consists of the flexible polygon spokes. Considering the NPT structure, the spokes undergo the tension-compression cyclic loading while the tire rolls. Therefore the spokes of NPT are required to have both stiffness and resilience under the cyclic tensile-compressible loading. In general, if a material has a high stiffness, it shows a low elastic strain limit. In this paper, using the auxetic honeycomb structure with negative poissons's ratio, the spokes of NPT tire are designed to have both stiffness and resilience. Finite element based numerical simulation of the contact pressure of a NPT is carried out with ABAQUS.

• Journal of Korea Port Economic Association
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• v.21 no.4
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• pp.1-31
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• 2005

Major companies in USA, Europe and Japan as well as even China and Russia put more overseas investment in Asian regions than before, while northeast Asian regional trade gets more attractive and important under the influence of China's super-speed economic growth. Possibly, it is expected that such ever-increasing gravity of regional trade will help spotlight the importance of local trade route considerably. In particular, northeast Asian region's economic briskness and step-up in international economic partnerships will expectedly contribute to much boosting up the quantity of goods transported via local coasting route. Thus, it is advisable that both Busan New port specialize in dealing with freights via East Sea rim, while Gwangyang port specialize in dealing with freights via Yellow Sea rim. Furthermore, it is required that both ports share some of their own roles as hub port and hub & spoke port respectively, so that both of them can be devoted to stepping up into northeast Asian hub ports.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.10a
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• pp.43-43
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• 1993

항공기 일정계획문제는 항공기, 승무원, 항공기 정비, 공항사용 등의 현재흐름을 시간과 공간의 개념을 도입한 Network상에 표현하여 분석하는 문제로서 여러가지 의사결정이 복합적으로 관련되어 있는 문제이다. 기존 연구에서는 운영상에 발생하는 많은 제약조건을 주어진 가정으로 처리하여 비교적 단순한 수리모형으로 최적해를 구하고자 했으므로 실제 적용에 한계를 가지고 있다. 또한, 최적해법으로 사용했던 최대흐름 알고리즘(Maximum Flow Algorithm)이나 단계적 접근법(Sequential Approach)으로는 변수의 수가 증가함에 따른 해법의 한계점을 가지고 있다. 본 연구에서는 1978년 미국의 항공규제완화 조치 후 많이 사용되고 있는 Hub and Spoke 노선상에서 항공기를 할당하는 문제로서, 보다 현실적인 제약요인을 포함하는 수리모형을 수립하고, Lagrangean Relaxation 기법을 사용하여 해를 구하고자 하였다.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.23-32
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• 2014

This study presents the prosodic characteristics of 'Motherese' and 'Teacherese (child care teacher and kindergarten teacher)'. 21 mothers and 24 teachers spoke to children in the child care center or kindergarten. Children are in their 4;00-6;11. Speech and articulation rate, number of accentual phrases (APs), number of intonational phrases (IPs), pitch-related factors (f0, pitch range, f0 standard deviation), and intonation slope (mean Absolute, f0, q-tone slope) were measured. 2 groups spoke 2 sentential types (interrogative_ alternative question, declarative_ coordinated sentence) in 2 situations (one accompanied with the children, the other done without children, but pretending as if they were in front of the children). The results indicate that teachers show more noticeable prosodic characteristics than mothers do.

• IE interfaces
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• v.11 no.1
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• pp.55-66
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• 1998

Fleet sizing and distribution of empty equipments are two of the most critical problems in managing transportation system. This paper develops a cost model for sizing a fleet and establishing decentralized redistribution polices of empty equipments by building from inventory theory of multi-echelon system in hub-and-spoke network. An analytical approach to determine control variables of redistribution policies in each terminal and fleet size of the transportation system is proposed and its results are validated by simulation model. Numerical experiments are conducted with respect to parameters of the model and test results for assumptions of the model are discussed.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.680-681
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• 2015

This paper proposes a comparative study of dual-airgap flux switching permanent magnet (FSPM) and spoke-type interior permanent magnet (S-IPM) machines equipped with phase-group concentrated-coil (PGCC) windings. Both of the investigated machines are the same size and material amounts which are compared at the same operating conditions. All the relevant machine performance including back electromotive force (EMF), cogging torque, and electromagnetic torque are analyzed by a 2-D time-stepping finite element method (FEM).

• Korean Management Science Review
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• v.18 no.2
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• pp.39-60
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• 2001

This Paper deals with a collaborative decision making procedure of web-based DSS for supply chain management (SCM). The seemingly autonomous DSS dedicated to each of mutually exclusive prob1em domains forms a communication network and cooperates each other for better SCM decision making. We a1so propose a hub-spoke information sharing model for the DSS network. In the hub-spoke model, an information hub at the center facilitates information exchange between DSS\\`s and controls the conversations defined by the series of XML messages between agents of DSS. A product ordering scenario where supply decision is triggered upon customer order is used to demonstrate the SCM decision procedure through a collaboration of the web-based DSS.

• Korean Journal of Child Studies
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• v.21 no.4
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• pp.69-79
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• 2000

This study compared the English and the Korean receptive competency of bilingual children with that of English and Korean monolingual children, respectively. The relation between English and Korean receptive competency of bilingual children was examined by age and gender. Subjects were 27 bilingual, 30 Korean monolingual, 24 English monolingual children. They were administered the revised form of the Peabody Pictures Vocabulary Test in Korean and English versions. Results show that bilingual children's Korean receptive competency is lower than those who spoke only Korean, and bilingual children's English receptive competency was a little lower than those who spoke only English, but the difference narrowerd with age. The relation between Korean and English competency in bilingual children was negative in 4- and 5-year-olds but became positive in 6-year-olds. This study shows that the two points-of-view on bilingual language development should be applied differently depending on children's age.