• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.1
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• pp.33-50
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• 2014

Though South Korea has world-class volume of Venture Capital Investment, as a share of GDP, early stage venture investments are still short, and investments are concentrated in high technology area and Capital area. Because of the high barriers to entry of the new IPO and M&A market, the venture capital companies undergo difficulties in profit. High-tech ventures face difficulties in raising money from outside investors due to information asymmetry between venture investors and venture companies. To resolve these problems, developed countries's government make a co-funding investment scheme with private sectors and design incentive mechanism such as receiving knowledge of the reputable investors' joint venture. Korean central and local government can benchmark those of things. For example, the expansion of the investment volume with private sector, region-specific matching fund and venture capital's exit path diversification such as M&A through the establishment of a business venture eco-system. At the same time, venture companies are to make an efforts to enhance the ability of screening for venture companies and the value for investment activities through a joint venture investments.

• The KIPS Transactions:PartB
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• v.10B no.7
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• pp.795-802
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• 2003

To live autonomously, intelligent agents such as robots or virtual characters need ability that recognizes given environment, and learns and chooses adaptive actions. So, we propose an action selection/learning mechanism in intelligent agents. The proposed mechanism employs a hybrid system which integrates a behavior-based method using the reinforcement learning and a cognitive-based method using the symbolic learning. The characteristics of our mechanism are as follows. First, because it learns adaptive actions about environment using reinforcement learning, our agents have flexibility about environmental changes. Second, because it learns environmental factors for the agent's goals using inductive machine learning and association rules, the agent learns and selects appropriate actions faster in given surrounding and more efficiently in extended surroundings. Third, in implementing the intelligent agents, we considers only the recognized states which are found by a state detector rather than by all states. Because this method consider only necessary states, we can reduce the space of memory. And because it represents and processes new states dynamically, we can cope with the change of environment spontaneously.

• Journal of the Korea Society of Computer and Information
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• v.16 no.9
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• pp.107-114
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• 2011

Because of boost of communications devices furnishing diverse services and rapid expansion of mobile business, good use and management of the existing network system become very important. Also, offering service corresponding with user communication requirement grades which vary widely in each person, is vital for communication service provider. In this paper, SGOSST, a mechanism of efficient network construction with minimum cost for network QoS is proposed. In experiments, though spending 252.97% more execution times, our SGOSST QoS network consumed 5.11% less connecting costs than the network constructed by weighted minimum spanning tree method. Therefore our mechanism can work well for efficient operation and service providing in the network formed with users and communication devices of various service requirement grade as smart/mobile equipment.

• Fire Science and Engineering
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• v.33 no.2
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• pp.30-38
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• 2019

Tracking, which is one of the main causes of electrical fires, is perceived as a physical phenomenon of electrical discharge. Hence tracking should be explained based on electric field analysis, conduction path by electron generation, and gas discharge physics. However, few papers have considered these details. This paper proposes a tracking mechanism including their effects on tracking progress. In order to prove this mechanism, a tracking experiment, an electric field analysis for the carbonization evolution model, and an explanation of the tracking process by gas discharge physics were conducted. From the tracking experiment, the current waveforms were measured at each stage of the tracking progress from corona discharge to tracking breakdown. The electric field analysis was carried out in order to determine the electric field on the surface of a dry-band and the high electric field region for electron generation during the generation and progress of carbonization. In this paper, the proposed tracking mechanism consisted of six stages including electron avalanche by corona discharge, accumulation of positive ions, expansion of electron avalanche, secondary electron emission avalanche, streamer, and tracking by conductive path. The pulse current waveforms measured in the tracking experiment can be explained by the proposed tracking mechanism. The results of this study will be used as the technical data to detect tracking phenomenon, which is the cause of electric fire, and to improve the proof tracking index.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.249-263
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• 2017

The expansion behavior of inflatable steel pipe rockbolt shows geometric nonlinearity due to its ${\Omega}-shaped$ section. Previous studies on the anchoring behavior of inflatable steel pipe rockbolt were mainly performed using theoretical method. However, those studies oversimplified the actual behavior by assuming isotropic expansion of inflatable steel pipe rockbolt. In this study, the anchoring behavior of the inflatable steel pipe rockbolt were investigated by the numerical method considering the irregularity of pipe expansion and other influencing factors. The expansion of inflatable steel pipe rockbolt, the contact stress distribution and the change of the average contact stress and the contact area during installation were analyzed. The contact stresses were developed differently depending on the constitutive behavior of rocks. Small contact stresses occurred in steel pipes installed in elasto-plastic rock compared to steel pipes installed in elastic rock. Also, the anchoring behaviors of the inflatable steel pipe rockbolt were different according to the stiffness of the rock. The steel pipe was completely unfolded in the case of the stiffness smaller than 0.5 GPa, but it was not fully unfolded in the case of the stiffness larger than 0.5 GPa for the given analysis condition. When the steel pipe is completely unfolded, the contact stress increases as the rock stiffness increases. However, the contact stress decreases as the rock stiffness increases when the steel pipe is not fully expanded.

• Journal of Integrative Natural Science
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• v.5 no.4
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• pp.220-228
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• 2012

District of Korea affected by westerly wind and heavy rainfall is predominantly distributed in the west and south of Honam district. So, this study is becoming a necessity. In this study, it is investigated that the characteristics of heavy rainfall occurred frequently in Honam district along the border of mT airmass after the end of rainy season due to atmospheric instability, lower (850 hPa) convergence and topographic effect. Our results show that heavy rainfall occurred in Honam district along the border of mT airmass results from the appropriate mechanism of the unstable vertical structure and moisture flux in the expansion and contraction of the border of mT airmass. All things considered, the improvement of the predictability of heavy rainfall occurred in Honam district along the border of mT airmass could be possible by the generalization of the results of this study.

• Korean System Dynamics Review
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• v.15 no.1
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• pp.51-74
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• 2014

Despite the high efficiency of nuclear power plant, people in Korea do not give approvals and supports the facilities because the risk of the accidents and incidents. In particular, the low level of safety culture is a crucial mechanism that damages the robustness of the NPP. By considering the various definitions of safety culture and analyzing the major reasons of incidents, the conceptual safety culture model is made by using Causal Loop Diagramming. For sustaining development of nuclear power, social supports, incentives and organizational learning are needed. It also requires the coordination of work schedules and the expansion of human resource for protecting the rules and procedures in NPP. Decommissioning aging nuclear power plants will prevent a serious accident. In order to promote the safety culture, Korea Hydro & Nuclear Power Corporation should disclose more information to the public and promote the internal and external communications.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.61-64
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• 2002

Fiber reinforced metal laminate(FRML) consists of alternations layers of metal and fiber reinforced composite. The difference in the coefficients of thermal expansion between metal and composite layer produces remarkable amount of thermal residual stresses between layers. Generally, FRML shows a tensile stress in metal layers, a compressive stress in composite layers after curing. In this study, the thermal residual stresses of several types of FRML are investigated to get the best combination of metal and composite which can reduce the thermal residual stresses. The residual stress level is compared with the strength of each layers to explain the fracture mechanism of FRML.

• Journal of the Korean Ceramic Society
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• v.29 no.12
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• pp.956-962
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• 1992

The predominant sintering mechanisms of low firing temperature ceramic substrate which consists of borosilicate glass containing alumina as a filler are the rearrangement of alumina particles and the viscous flow of glass powders. In this system, sintering condition depends on the volume ratio of alumina to glass and on the particle size. When the substrate contains about 35 vol% alumina filler and the average alumina particle size is 4 $\mu\textrm{m}$, the best firing condition is obtained at the temperature range of 900∼1000$^{\circ}C$. The extensive rearrangement behavior occurs at these conditions, and the optimum sintering condition is attained by smaller size of glass particles, too. The formation of cristobalite during sintering causes the difference of thermal expansion coefficient between the substrate and Si chip. This phenomenon degradates the capacity of Si chip. Therefore, the crystallization should be prevented. In the alumina filled borosilicate glass system, the crystallization does not occur. This effect may have some relation with aluminum ions in alumina. For aluminum ions diffuse into glass matrix during sintering, functiong as network former.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.2
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• pp.119-124
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• 2016

According to the expansion of smartphone penetration and development of wearable device, personal context information can be easily collected. To use this information, the context aware recommender system has been actively studied. The key issue in this field is how to deal with the context information, as users are influenced by different contexts while rating items. But measuring the similarity among contexts is not a trivial task. To solve this problem, we propose context aware post-filtering to apply the context compensation. To be specific, we calculate the compensation for different context information by measuring their average. After reflecting the compensation of the rating data, the mechanism recommends the items to the user. Based on the item recommendation list, we recover the rating score considering the context information. To verify the effectiveness of the proposed method, we use the real movie rating dataset. Experimental evaluation shows that our proposed method outperforms several state-of-the-art approaches.