• Journal of Technology Innovation
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• v.6 no.2
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• pp.122-158
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• 1998

This study empirically examined different patterns of collaborative R&D project with their key success factors(KSFs), using data from 82 projects in the Korean electronic parts industry. The patterns of R&D collaboration were categorized into 4 types by two criteria development motive(technology Push/market pull) and Project initiator (focal firm/partner). The bivariate relationships revealed that project characteristics (technological complexity, market uncertainty), management characteristics (participation in project formulation), problem solving characteristics(problem solving performance of the focal firm, users active role in problem solving, active role of university or research institute in problem solving) and success rates appear to be different among four types of collaboration. Each type of collaborative R&D projects also had different KSFs. The KSFs of type 1 (technology Push and focal firm initiation), for instance, include the strategic importance of the project, focal firms share of cost, active role of university or research institute in problem solving, while those of type 4(market pull and customer initiation) cover reliability of partner relationship, a time at partners involvement, information sharing. The findings suggest that the different contingencies brought different patterns and KSFs of collaborative R&D project, since different information, resources, and partners roles were needed to successfully implement the projects according to development motive and project initiator Finally, managerial, policy, and theoretical implications for the collaborative R&D activities in the Korean electronics parts industry were discussed, based on empirical results of this study.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1936-1939
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• 2002

Much recent attention on wireless technologies s put on topology-less wireless network, in which all nodes an be mobile and can communicate over wireless links, due to its ease of deployment, high flexibility and low expenses. One key in topology-less wireless network is mobile base stations (MBSs), which provides access points or mobile terminals (MTs) to wireless backbone network. MBSs can move to anywhere in accordance with changes in geographical distribution of MTs. They serve as dynamic odes. However, in order to utilize network resources and take full advantage of this topology-less network, MBSs must move to suitable position according to the current tate of network use. Moreover, MBSs have to consider the distance among them to avoid the crash and gap area of MBSs. Therefore, this paper proposes MBS movement algorithm by implementing push-pull method to fulfill the corporation of MBSs and considering the center of covered MTs or centroid to satisfy the MT coverage. From the simulation results, the proposed algorithm increases the performance of system when comparing with the centroid-based algoriom〔7〕, such as coverage area, MT coverage and call drops rate.

• Steel and Composite Structures
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• v.42 no.2
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• pp.191-207
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• 2022

Undoubtedly, the employment of direct bond interaction between steel and concrete is preceding the other mechanisms because of its ease of construction. However, the large scatter in the experimental data about the issue has hindered the efforts to characterize bond strength. In the following research, the direct bond interaction and bond-slip behavior of CFTs with circular cross-section were examined through repeated load-reversed push-out tests until four cycles of loading. The influence of different parameters including the diameter of the tube and the use of shear tabs were assessed. Moreover, the utilization of expansive concrete and external spirals was proposed and tested as ways of improving bond strength. According to the results section dimensions, tube slenderness, shrinkage potential of concrete, interface roughness and confinement are key factors in a natural bond. Larger diameters will lead to a considerable drop in bond strength. The use of shear tabs by their associated bending moments increases the bond stress up to eight times. Furthermore, employment of external spirals and expansive concrete have a sensible effect on enhancing bonds. Macro-locking was also found to be the main component in achieving bond strength.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.745-749
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• 2006

The appearance of wirelsss internet service made accessing easier than existing mobile devices. Due to the properity of mobile devices, we can easily obtain his/her profile information compared to a wired internet service. It enables to provide a personalized service through mobile devices. In this paper, we propose a recommendation service based on collaborative filtering method and a content push service. Using users' profile information, we recommand a target user's favoriate content. The recommanded contents are stored in mobile device through the push service. When we connect a wireless internet service, our mobile push service starts to cache from user's favorite contents. Especially, when we select a large mobile content, our system can reduce a download time by using our recommandation service. Also, in case of a connectionless, we can use a cached data from pushed content in our mobile device.

• Journal of Advanced Navigation Technology
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• v.18 no.6
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• pp.588-593
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• 2014

Recently, the smart devices has been possessed by a large majority of the adult, and offered various personalization services. This paper proposed the lightweight Intelligent Image Security System that notice the existence of any intruder in real time at the place of requiring the security by using smart device. The proposed image security system recognized whether or not intruder exists using the difference frame on the basis of Integral Image and the dynamic background updating algorithms. The intrusion notification is achieved by using the GCM push server that send massages in the application unit of user mobile device, and the SMTP mail server which is use of e-mail standard protocol. In case of the occurrence of intruder, GCM push server send an push-massage by the private mobile device, and SMTP mail server send the intruder's photograph and intrusion time. By the convergence of the various image processing algorithms and the performance of smart device, The proposed image security system can be applied to the various Intelligent Image Security field.

• Journal of radiological science and technology
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• v.41 no.6
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• pp.539-543
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• 2018

Telometer is a supplementary filming device that improves the image quality and minimizes the motion unsharpness by enhancing the reproducibility of diagnostic images because it applies constant pressure (force) to the affected area. The stress-radiogram which is widely used to provide the o-bjective quantitative stability of knee ligament is reported in literature as the most suitable method to evaluate the stability of ligament and it is advised to use the Telometer. In order to evaluate the image reproducibility of the Telometer, the collateral ligament which is the most vulnerable among the ligaments consisting of the knee joint, the stress-radiogram was executed in the order of the Telometer, the push pull gauge and the conventional stress radiogram. Then, SPSS (Statistical Package for the Social Science) for Windows 22.0 was used for comparison and evaluation. According to the results of comparison and evaluation, the standard errors and standard deviations became smaller in the order of the Telometer, the push pull gauge, the conventional stress radiogram while the image reproducibility was higher in the order of the Telometer, the push pull gauge, the conventional stress radiogram. Therefore, it is considered that the use of the TELOS for stress-radiogram would enhance the quality of patient diagnostic images and the work performance of radiologists.

• Journal of Korea Technology Innovation Society
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• v.21 no.2
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• pp.491-521
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• 2018

This paper aims to uncover success factors in technology transfer of Korean government sponsored research institutes. It presents an analytical framework of technology transfer integrating factors concerning actors, object and process. Qualitative analysis mainly based on In-depth interviews is designed and conducted to examine characteristics, similarities and differences of three types technology transfer including a supply-push model, a demand-pull model, and an interactive model. Empirical results show that capabilities and experiences of researchers, capabilities and willingness of the company and active communications in the technology transfer appear to be important factors. In particular, it was found that technology transfer was led by TLO in the demand-pull model. In addition, the demand-pull and interactive approaches tends to be more effective in the technology development and transfer process compared to the supply-push model. In other words, market-oriented R&D is needed instead of technology-driven R&D. This paper also pointed out that one of the major factors in successful technology transfer is the enhancement of TLO capacity, and the improvement of recognition about TLO.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.708-712
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• 2001

A new phase-shifted parallel-input/series-output (PI SO) dual inductor-fed push-pull converter for high-power step­up applications is proposed. This converter is operated at a constant duty cycle and employs an auxiliary circuit to control the output voltage with a phase-shift between the two modules. It features a voltage conversion characteristic which is linear to changes in the control input, and high step-up ratio with a greatly reduced switch turn-off stress resulting in a significant increase in the converter efficiency. It also shows a low ripple content and low root-mean-square (RMS) current in the output capacitor. The operational principle is analyzed and a comparative analysis with the conventional pulse-width-modulated (PWM) PISO dual inductor-fed push-pull converter is presented. A 50kHz, 800W, 350Vdc prototype with an input of 20-32Vdc has also been constructed to validate the proposed converter. The proposed converter compares favorably with the conventional counterpart and is considered well suited to high-power step-up applications.

• Tribology and Lubricants
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• v.27 no.3
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• pp.140-146
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• 2011

A miniature pendular type impact testing machine was designed and developed, adopting a magnetic powder brake in order to investigate tensile and shear behavior of a small solder ball at high speed. In this testing system, the potential energy of the pendulum is transferred into the impact energy during its drop. Then, the impact energy is transmitted through the striker which is connected to the push rods to push the specimen for tensile loading. The tensile behavior of lead-free solder ball in diameter of 760 ${\mu}m$ was successfully investigated in a speed range of 0.15 m/s~1.25 m/s using this designed device. The maximum tensile strength of the solder joint decreases with the loading speed in the testing condition. The maximum tensile strength of the joint was 56 MPa in the low speed region.

• Journal of Power Electronics
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• v.1 no.2
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• pp.78-87
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• 2001

A new high-power step-up based on the two-module parallel-input (PISO) modular dual inductor-fed push-pull converter is proposed. The proposed converter is operated at a constant duty cycle and employs and auxiliary circuit to control the output voltage with a phase-shift between two modules. It shows a high efficiency due to the greatly reduced switch turn-off stress. It also shows a high and linear voltage conversion ratio, low current stress in the output capacitor, and fast control-to-output dynamics. The operation principles and the mathematical models of the proposed converter are presented. Features of the proposed converter are discussed in comparison with the two-module PISO modular dual inductor-fed push-pull converter. Also, experimental results from a 50kHz, 800W, 350 Vdc prototype with an input voltage range of 20-32 Vdc are provided to confirm the validity of the proposed converter. The new converter compares favorably with the conventional counterpart, and is considered well siuted to high-power step-up applications.