• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.1
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• pp.5-19
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• 2015

Literatures on open innovation have two major limitations. First, either on a firm level or on an industry level did they analyze the open innovation issues. The results of a firm's innovation can be diffused through the whole network and the firm can learn back from the network knowledge. Prior literatures did not consider the feedback loop among firms and network in which the firms are involved. Second, most open innovation research had a static perspective on firm's innovation performance. Since the diffusion, spill-over and learning among network members are involved over time, the open innovation is intrinsically dynamic. From the dynamic perspective, we can appreciate the fundamental attributes of the open innovation network which involves diverse firms, research institutes, and universities. In order to overcome the limitations, we suggest a dynamic model for open innovation network. We build an agent-based model which consists of heterogeneous firms. The firms are connected through a scale-free network which is formed by preferential attachment. Through the diverse scenario of simulation, we collect massive data on the firm level and analyze them both on firm and industry level. From the analysis, we found that, on industry level, the overall performance of open innovation increases as the internal research capability, absorptive capacity, and learning curve coefficient increase. Noticeably, as the deprecation rate of knowledge increases, the variability of knowledge increases. From the firm level analysis, we found that the industry-level variables had a significant effect on the firm's innovation performance lasting through all the time, whereas the firm-level variables had only on the early phase of innovation.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.1
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• pp.61-66
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• 2014

Lung cancer is still the number one cause of death from cancer worldwide. The clinical effect of platinum-based chemotherapy for non-small cell lung cancer is constrained by the resistance to drug. To overcome chemo-resistance, various modified treatment including combination therapy has been used, but overall survival has not been improved yet. In this study, chemo-resistant lung cancer cells, A549/Cis and H460/Cis, were developed by long-term exposure of cells to cisplatin and the proliferative capability of these resistant cells was verified to be reduced. We found cytotoxic effect of epigallocatechin gallate (EGCG), a major catechin derived from green tea, on both the parental lung cancer cells, A549 and H460, and their cisplatin resistant cells, A549/Cis and H460/Cis. ELISA and Western blot analysis revealed that EGCG was able to increase interlukine-6 (IL-6) production per cell, whereas its downstream effector Signal transducers and activators of transcription 3 (STAT3) phosphorylation was not changed by EGCG, indicating that IL-6/STAT3 axis is not the critical signaling to be inhibited by EGCG. We next found that EGCG suppresses the expression of both Axl and Tyro 3 receptor tyrosine kinases at mRNA and protein level, explaining the cytotoxic effect of EGCG on lung cancer cells, especially, regardless of cisplatin resistance. Taken together, these data suggest that EGCG impedes proliferation of lung cancer cells including their chemo-resistant variants through downregulation of Axl and Tyro 3 expression.

• Journal of Technology Innovation
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• v.17 no.1
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• pp.69-95
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• 2009

This paper examines the motives for location decisions of startups and dynamics of cluster growth. Because the location decision is intrinsically strategic choice by entrepreneurs, it is an interplay of three critical forces; cost-benefit of the choice, R&D ability of new entrants, and R&D capability of incumbents in clusters. The effect of knowledge spillovers influences the cluster growth like a double-edge sword; both a positive effect of technology learning and a negative effect of knowledge de-learning. Using data on 710 bio-tech venture firms in Korea, this paper tests the hypotheses about the factors influencing the growth of the cluster. The empirical analyses suggested that early entrepreneurial activity in the clustered regions were important, however other factors such as the organizational legacy, internal dynamics inside a cluster, and the existence of cooperation norm in the cluster, affected long term viability of the cluster.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.747-756
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• 2016

In this paper, a connection details for precast arch structures was proposed. Experiments were performed to evaluate structural performance of the loop connection details satisfying current design requirements and of alternative details for improvement of constructability. Precast arch specimens considering the current design requirements showed higher structural capacity than a cast-in-place arch specimen. Crack width at the connection of arch crown showed smaller value than 0.2 mm due to increased compression force by the applied vertical load. Strengthening by wire-mesh at notch area of the connection improved initial crack control capability. Connection detail with couplers and headed bars showed similar capacity to the reference specimen. The alternative details to improve constructability of reinforcements can be used without decreasing structural performance. Specimens with smaller internal diameter of mandrel and shorter loop splicing than the current design codes showed worse behavior in terms of crack width control.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.661-673
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• 2020

The quarter-core simulation of BEAVRS Cycle 2 depletion benchmark has been conducted using the MCS/CTF coupling system. MCS/CTF is a cycle-wise Picard iteration based inner-coupling code system, which couples sub-channel T/H (thermal/hydraulic) code CTF as a T/H solver in Monte Carlo neutron transport code MCS. This coupling code system has been previously applied in the BEAVRS benchmark Cycle 1 full-core simulation. The Cycle 2 depletion has been performed with T/H feedback based on the spent fuel materials composition pre-generated by the Cycle 1 depletion simulation using refueling capability of MCS code. Meanwhile, the MCS internal one-dimension T/H solver (MCS/TH1D) has been also applied in the simulation as the reference. In this paper, an analysis of the detailed criticality boron concentration and the axially integrated assembly-wise detector signals will be presented and compared with measured data based on the real operating physical conditions. Moreover, the MCS/CTF simulated results for neutronics and T/H parameters will be also compared to MCS/TH1D to figure out their difference, which proves the practical application of MCS into the BEAVRS benchmark two-cycle depletion simulations.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.4
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• pp.11-17
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• 2017

Organizations are experiencing an ever-growing concern of how to prevent confidential information leakage from internal employees. Those who have authorized access to organizational data are placed in a position of power that could well be abused and could cause significant damage to an organization. In this paper, we investigate the task of detecting such insider through a method of modeling a user's normal behavior in order to detect anomalies in that behavior which may be indicative of an data leakage. We make use of Hidden Markov Models to learn what constitutes normal behavior, and then use them to detect significant deviations from that behavior. Experiments have been made to determine the optimal HMM parameters and our result shows detection capability of 20% false positive and 80% detection rate.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.50-56
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• 2016

This paper proposes the architecture and design of intra prediction circuit for a multi-decoder supporting UHD images. The proposed circuit supports not only the latest video compression standard HEVC but also H.264. In addition to the basic function of performing intra prediction, this circuit has the capability of performing the reference sample filter operation defined in the H.264 standard, and the smoothing and strong sample filter operations defined in the HEVC standard. We reduced the circuit size by sharing the circuit blocks for common operations and internal storage, and improved the circuit performance by parallel processing. The proposed circuit was described at RTL using Verilog HDL and its functionality was verified by using NC-Verilog of Cadence. The RTL circuit was synthesized by using Design Compiler of Synopsys and 130nm standard cell library. The synthesized gate-level circuit consists of 69,694 gates and processes 100 ~ 280 frames per second for 4K-UHD HEVC images at the maximum operation frequency of 157MHz.

• Journal of the Korean Electrochemical Society
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• v.4 no.1
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• pp.1-5
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• 2001

Composite ratio of $LiMn_2O_4$ in cathode was optimized as function of specific surface area. Binder has to be used as possible as little, and it should maintain adhesive property between cathode composite and current collector even though in electrolytes. For this purpose, We used 'Hot Roll Pressing' method, and it was effective. To prevent separation of cathode composite from current collector, PVDF(Polyvinylidenefluoride) has to be mixed more than $1.1\%$ in weight ratio to sum of surface area of lithium manganese oxide and conducting agents. Specific internal resistance was reduced as by increasing electrical conductivity of cathode. And Ratio of 2C rate discharge capacity to 0.2C rate discharge capacity was increased by $17\%$, as increasing electrical conductivity from 0.019 mS/cm to 0.036 mS/cm.

• Journal of Information Technology Application
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• v.3 no.2
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• pp.83-102
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• 2001

Internet-based shopping business spread rapidly in Korea. Companies are trying to develop and use various strategic competences. The strategies employed by those companies include activities related to the design of shopping site, market positioning, assistance of purchasing process, payment mechanism, and provision of various consumer services. However, the success of these strategies depends on various environmental factors and internal capability of the companies. In this study, I examined four successful Internet shopping mall companies and compared them to draw useful guidelines for Internet-based intermediary business. These four companies were selected because they are all considered successful by now, but brought different background. We found follows. First, each company tried to economize their own historical and developmental background. All of the selected companies were alike in their focus on the whole Internet user group. Customer needs analysis was performed more systematically. The Importance of customer information and the use of it are not sufficient. Second, Each companies consistently emphasized the importance of market-related activities. Despite the differences in initial states, all companies used similar strategies and had similar focus in target market and products. Conclusively, implications from this research for Internet shopping business can be summarized as follows. First, One of the important future directions for Internet shopping mall business is to broaden target market. Second, the provisions of carefully designed customized services are one success factor. Third, As customer traffic increased, the provision of differential customer service becomes a key success factor.

• Smart Structures and Systems
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• v.26 no.5
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• pp.605-617
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• 2020

In this study, the experimental tests for the direct tensile strength measurement of Ultra-High Performance Concrete (UHPC) were numerically modeled by using the discrete element method (circle type element) and Finite Element Method (FEM). The experimental tests used for the laboratory tensile strength measurement is the Compressive-to-Tensile Load Conversion (CTLC) device. In this paper, the failure process including the cracks initiation, propagation and coalescence studied and then the direct tensile strength of the UHPC specimens measured by the novel apparatus i.e., CTLC device. For this purpose, the UHPC member (each containing a central hole) prepared, and situated in the CTLC device which in turn placed in the universal testing machine. The direct tensile strength of the member is measured due to the direct tensile stress which is applied to this specimen by the CTLC device. This novel device transferring the applied compressive load to that of the tensile during the testing process. The UHPC beam specimen of size 150 × 60 × 190 mm and internal hole of 75 × 60 mm was used in this study. The rate of the applied compressive load to CTLC device through the universal testing machine was 0.02 MPa/s. The direct tensile strength of UHPC was found using a new formula based on the present analyses. The numerical simulation given in this study gives the tensile strength and failure behavior of the UHPC very close to those obtained experimentally by the CTLC device implemented in the universal testing machine. The percent variation between experimental results and numerical results was found as nearly 2%. PFC2D simulations of the direct tensile strength measuring specimen and ABAQUS simulation of the tested CTLC specimens both demonstrate the validity and capability of the proposed testing procedure for the direct tensile strength measurement of UHPC specimens.