• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.5614-5633
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• 2018

Mobile Edge Computing (MEC) and Wireless Power Transfer (WPT) are both recognized as promising techniques, one is for solving the resource insufficient of mobile devices and the other is for powering the mobile device. Naturally, by integrating the two techniques, task will be capable of being executed by the harvested energy which makes it possible that less intrinsic energy consumption for task execution. However, this innovative integration is facing several challenges inevitably. In this paper, we aim at prolonging the battery life of mobile device for which we need to maximize the harvested energy and minimize the consumed energy simultaneously, which is formulated as residual energy maximization (REM) problem where the offloading ratio, energy harvesting time, CPU frequency and transmission power of mobile device are all considered as key factors. To this end, we jointly optimize the offloading ratio, energy harvesting time, CPU frequency and transmission power of mobile device to solve the REM problem. Furthermore, we propose an efficient convex optimization and sequential unconstrained minimization technique based combining method to solve the formulated multi-constrained nonlinear optimization problem. The result shows that our joint optimization outperforms the single optimization on REM problem. Besides, the proposed algorithm is more efficiency.

• 재무관리연구
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• 제25권1호
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• pp.177-196
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• 2008

본 연구는 유사한 혹은 동일한 산업에 속해 있는 두 기업이 공동사업(joint venture)을 수행하는 과정에서 이익을 분배하는 메카니즘을 분석한다. 두 기업이 동의할 수 있는 '공정한' 이익분배와 함께 자원배분의 효율성을 달성할 수 있는 의사결정구조를 모색한다. 공동사업은 한 기업이 설비를 제공하고, 다른 기업이 제품을 생산하고 판매하는 형태로 진행되는 경우를 상정하고 있다. 본 연구의 분석결과는 공동사업의 의사결정 구조를 적절히 고안하면 사회적 효율성을 충족하는 균형에 도달할 수 있음을 시사한다. 동일 기업집단 내의 공동사업과 같이 이익분배(이전가격)가 사전에 정해져 기업들의 사적 유인이 통제될 수 있는 상황 뿐 아니라, 독립적 기업들의 공동사업에서도 판매기업이 단독으로 이전가격을 결정하는 구조를 배제하면 효율적인 결과를 낳을 수 있음을 보인다.

• 대한기계학회논문집A
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• 제29권2호
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• pp.220-227
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• 2005

In this study, stress-displacement analytic solutions are obtained by a shear lag modeling method constructed for the spliced joint area with a splicing gap in the fiber metal laminate (FML). This gap can be empty or be filled with an adhesive material of elastic modulus $E_a$. Two splicing types are considered for spliced shear models, one for spliced in the center metal layer, the other for spliced in the outer metal layer. It is shown that from the viewpoint of the load transfer efficiency and the avoidability of disbond generation due to the shear and axial stresses at the interface between metal layer and composite layer of the gap-front in the spliced area, the center spliced type (k=2) is much preferable to the outer spliced type (k=1).

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.171-176
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• 2001

Recent building structures are superior in its ability but they are light and flexible, and so have problems of vibration. In general, the problem of vertical vibration is not considered in structural design. However, in terms of serviceability for inhabitants in buildings, the estimation of vibration in design stage is important. Characteristics of vertical vibration is changed by modeling method of beam-column joint. To check the characteristics of vertical vibration, many tests and analyses were conducted on constructing building in Seoul. Results of tests and analyses were compared using transfer function. As a results, to check the vertical vibration, the cramp ratio of beam-column joint must be considered and reduced in structural design.

• Archives of Reconstructive Microsurgery
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• 제9권2호
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• pp.134-138
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• 2000

Arthrodesis of the ankle joint is inevitable in the cases of severe arthrosis or defective bony structures around ankle joint. There have been many kinds of arthrodesis methods were introduced. In cases with failed athrodesis with previous arthrodesis surgery and neuropathic joints have difficulty to achieve fusion of joint with conventional methods. Authors underwent four cases of ankle fusion with vascularized fibular graft from 1997 in the cases of three failed fusions and one diabetic neuropatic joint. Two of four performed free vascularized fibular transplantation from contralateral side leg with microvascular anastomosis, two of four performed with pedicled fibular transposition to the ankle joint in same side leg. Three of four cases achieved arthrodesis average 9.2 months after surgery, one case was failed due to vascular thrombosis of the anastomosed site in diabetic neuropathic condition. The result of this technique revealed 75%(three of four) success rate and longer bone union time required. However, in these cases had no recommendable options with conventional bone graft and additional ankle joint fusions procedure because of poor bone quality and defect of distal tibia and talus portions. Free vascualrized fibular transfer to the failed athrodesis of ankle joint is one of the effective alternative methods in failed ankle fusion cases, especially the quality of the bone around previous fusion site is poor.

• International Journal of Automotive Technology
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• 제8권6호
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• pp.723-730
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• 2007

The typical design of automotive driveshafts generally utilizes Constant Velocity(CV) joints as a solution to NVH. CV joints are an integral part of vehicles and significantly affect steering, suspension, and vehicle vibration comfort levels. Thus, CV joints have been favored over universal joints due to the constant velocity torque transfer and plunging capability. Although CV joints are common in vehicle applications, current research works on modeling CV joint friction and assumes constant empirical friction coefficient values. However, such models are long known to be inaccurate, especially under dynamic conditions, which is the case for CV joints. In this paper, an instrumented advanced CV joint friction apparatus was developed to measure the internal friction behavior of CV joints using actual tripod-type joint assemblies. The setup is capable of measuring key performance of friction under different realistic operating conditions of oscillatory speeds, torque and joint installation angles. The apparatus incorporates a custom-installed triaxial force sensor inside of the joint to measure the internal CV joint forces(including friction). Using the designed test setup, the intrinsic interfacial parameters of CV joints were investigated in order to understand their contact and friction mechanisms. The results provide a better understanding of CV joint friction characteristics in developing improved automotive driveshafts.

• 무역상무연구
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• 제18권
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• pp.159-188
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• 2002

International joint ventures are usually formed and managed by domestic companies and foreign investors for the common objectives. They offer an opportunity for each partner to benefit significantly from the comparative advantages of the other. Local partners bring knowledge of the domestic market; familiarity with government bureaucracies and regulations; understanding of local labor markets; and existing manufacturing facilities. Foreign partners can offer advanced process and product technologies, management know-how, and access to export markets. In Korea, joint ventures have been encouraged to usher in foreign investors with foreign currency capital badly needed during the IMF financial crisis. In the meantime, Korean laws and regulations with respect to joint ventures have been largely overhauled to promote foreign direct investment (FDI) both inbound and outbound. They include four types of FDI, i.e., acquisition of foreign stocks, provision of long-term loans, participation in joint operations like resources development, and establishment of foreign offices. From the legal point of view, the formal joint venture agreement must be an offspring of a series of tough negotiations between domestic and foreign partners. They usually stress the long-term relationship with the good will and dedication to each other, and restrict the free transfer of stocks. Both partners are earnestly interested in the ownership and management of the joint venture. So they keep a close eye on the articles of incorporation, changes of business environment, conflict resolution methods, transparency of accounting and other financial matters. When a multinational corporation (MNC) is involved in the joint venture, conflicts over management strategies, marketing and other issues take place more often than not between the MNC and local partners. We have to pay attention to joint ventures, particularly, in China and North Korea. As witnessed in other transition economies, China is eagerly bringing in foreign direct investments for the development of nation's economy. China encourages foreign investors to establish ordinary joint ventures, contractual joint ventures, solely invested foreign capital companies and jointly operated development companies with local partners. In North Korea, however, joint ventures have a different meaning like contractual joint ventures in China, in which North Korean partners have an initiative in the management. Rather, jointly operated companies or simply processing-for-wage companies are recommended in view of the unpredictable legal infrastructure in North Korea.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
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• pp.475-480
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• 1998

The composite framed structures, consisting of RC columns and steel beams more popular in korea because of their efficiency and quality. However the force transfer mechanisms between the column and beam may by very complicated since the materials of columns and beams are different. This study develops "the column penetration joint" which the web of steel beam doesn't penetrate and which could improve the strength, deformation, and energy dissipation capacities compared to existing composite joints. It is the concrete-filled square tube joint with the exterior diaphragms and the cruciform stiffening plates. This study evaluated the strength of RC column penetration to steel beam connection by analyzing the results of partial experiments, and reviewed the applicability the strength formula through the comparison of tested results of joint experiment.

• 열처리공학회지
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• 제15권5호
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• pp.228-233
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• 2002

The characteristics of the induction heating process are analyzed for the joint of nylon and metal. The temperature of metal surface is measured using thermocouples. The relations of temperature and induction heating parameters are analyzed. Heat equation models are constructed and the temperature distribution is predicted using Fluent. The effects of heating parameters on the joint strength are evaluated. Finally, the optimal parameters of induction heating process are proposed as 16kW and 6 seconds.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.302-307
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• 2005

Love wave and Rayleigh wave are the major elastic waves belonging to the category of the surface wave. The fact that Love wave is not contaminated by P-wave which makes Love wave superior to Rayleigh wave and other body waves. Therefore, the information that Love wave carries is more distinct and clearer than the information of Rayleigh wave. Based on theoretical research, the joint inversion analysis which is used both Love wave dispersion information and Rayleigh wave dispersion information was proposed. Purpose of the joint inversion analysis is to improve accuracy and convergency of inversion results utilizing that frequency contribution of each wave is different. This analysis technique is consisted of the forward modeling using transfer matrix, the sensitivity matrix determined to the ground system and DLSS(Damped Least Square Solution) as a inversion technique. The application of this analysis was examined through the field test.