• KDI Journal of Economic Policy
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• v.34 no.2
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• pp.1-15
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• 2012

We develop an identity choice model within the context of a stereotyping-cum-signaling framework. The model allows us to explore implications of the fact that, when individuals can choose identity, then the distribution of abilities within distinct identity groups becomes endogenous. This is significant because, when identity is exogenous and if the ability distributions within groups are the same, then inequality of group reputations in equilibrium can only arise if there is a positive feedback between group reputation and individual human capital investment activities (Arrow, 1973; Coate and Loury, 1993). Here we show that when group membership is endogenous then the logic of individuals' identity choices leads there to be a positive selection of higher ability individuals into the group with a better reputation. This happens because those for whom human-capital-investment is less costly are also those who stand to gain more from joining the favored group. As a result, ability distributions within distinct groups can endogenously diverge, reinforcing incentive-feedbacks. We develop the theoretical framework that can examine the positive selection and the endogenous group formation. The model implies that inequality deriving from stereotyping of endogenously constructed social groups is at least as great as the inequality that can emerge between exogenously given groups.

• Journal of the Korean Academic Society of Industrial Cluster
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• v.1 no.1
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• pp.29-46
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• 2007

The purpose of this paper is to analyses current status and issues of cluster formation and extract policy implications. To this end, the questionnaire which surveyed the level of cluster formation were executed targeting the actors of regional innovation projects(RIPs). The results show that the situations and development stage of the cluster formation between capital region and non-capital region, large cities and small and medium sized cites are different. The level of clustering is also satisfactory, which is a requirement for cluster formation at its early stage. However, the capacity for phase II of cluster growth is not sufficient yet in terns of relationships between ventures and large corporations, institutions supporting management, finance and marketing, researchers from each individual sector of strategic industries and spin-off fines. Therefore, RIPs should be promoted with different policy tools for various regions that are devised according to the varying development stage of each region. The location of RIPs should be determined considering efficiency rather than equity, clustering rather than decentralization, and specialization rather than multiple development. In the long term, developed regions should pursue balanced regional development, with underdeveloped regions targeting specialization.

• Journal of Korean Society of Transportation
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• v.29 no.6
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• pp.129-136
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• 2011

Variable Message Signs have been used for providing information on the current traffic conditions. However, it is considered more important to achieve optimal traffic allocation among the alternative routes by strategic VMS information provision. Fuzzy control is very effective and efficient to deal with such systems that are too complex and uncertain to build mathematical models. In this paper, a fuzzy feedback controller for VMS is proposed, whose goal is to achieve the travel time equilibrium between the two alternative routes. The performance of the suggested controller is implemented and examined using MATLAB/Simulink. More robust controller applicable to a real highway network is suggested for the further research.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.1
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• pp.47-58
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• 2014

In this research, the initial sizing of a HALE(High Altitude Long Endurance) UAV which uses solar power and hydrogen fuel cell as an alternative energy was performed. Instead of a wing box type, a glider type was chosen since it is relatively easy to get a data thanks to many researches abroad. Maximum takeoff weight is around 150Kg and the propulsion system is composed of motor, propeller, solar cell, and hydrogen fuel cell which can be recharged through electrolysis. Maximum takeoff weight was estimated as aspect ratio, wing span, wing area change while considering energy balance of required energy which is necessary for flight during the entire day and available energy which can be taken from the solar cell.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.169-175
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• 2004

The purpose of this study is to present the detailed national strategy, from the financial point of view, for global logistics center in the Northeast Asia using the Balance Scorecard Model(BSC) as well as SWOT analysis. It is a core national challenge for Korea to emerge as a logistics hub of the Northeast Asian region, which is directly related to its very existence in the 21st century. In the process of formulating such a vital strategy, various aspects must be considered In conclusion, this study has successfully deduced the preemptive strategy for exceeding other competitors from the financial (budgetary) perspective and the logistics strategy from inner process standpoint of maximizing logistics outcome by carrying out efficient logistics policy.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.71-78
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• 2004

This paper presents a game-theoretic model of information transmission for variable message sign(VMS) operations. There are one VMS operator and many drivers as players. Operator wants to minimize the total travel time while the drivers want to minimize their own travel time. The operator who knows the actual traffic situation offers information strategically. The drivers evaluate the information from operator, and then choose the route. We model this situation as a cheap-talk game which is a simplest form of Bayesian game. We show that there is a possibility that the operator can improve the traffic efficiency by manipulating the electric signs at times. Indeed, it is an equilibrium of the game. This suggests that the operator must consider the strategic use of VMS system seriously.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.5
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• pp.359-366
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• 2015

TMJ(TemporoMandibular Joint) is considered as the most important articulation in human body for maintaining the balance. Thus it is one of the main treatment areas in Chiropractic. Instead of Chiropractic treatment, NOSICK, a TMJ balancing device, can be used. As there is no such device to quantify the effect of NOSICK, a system was developed to measure the effect of NOSICK. This system is composed of stereo vision, infrared lights, and infrared through filter, etc. It requires optical markers for the measurement. 8 land markers were selected from the face which will show different displacement as NOSICK is applied. 11 test subjects were measured with the system developed with and without NOSICK applied. Quantifiable displacement of markers before and after applying NOSICK was successfully measured with the system developed.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.2
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• pp.127-135
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• 2003

The motions used in throwing place tremendous stresses on the soft tissues about the player's shoulder. In order to throw successfully, the shoulder complex must be capable of excessive motion, while maintaining stability of the glenohumeral joint. Injuries to the throwing player can result from acute trauma, but more commonly can be a result of overuse injuries from the repetitive throwing activity. Inbalance in the muscles and soft tissue about the shoulder can result in an injury secondary to abnormal biomechanics of the glenohumeral complex. The preventive measure a throwing player can take in order to maintain a healthy throwing shoulder is to participate in a regular shoulder strengthening program. It is when the muscles about the shoulder become imbalanced, secondary to either injury or relative weakness, that instability and injury can occur. By understanding the pitching motion and the relative contribution of the muscles, the treating physician has a framework on which to build knowledge regarding physical findings and diagnosis of shoulder injuries in throwing players. Once a diagnosis is made. a successful treatment plan may be developed for the player, including both conservative and , at time surgical means.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.1005-1014
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• 2010

When reader collect tags, we found that they tend to get together to specific interface in Multi-Interface Multi-Channel 2.4GHz Active RFID system. To solve this problem, we designed the LP-Combind and AP-Balanced protocol for load distribution between interfaces, then verified its superiority of the performance through the simulation. There are three problems to implement designed protocols in hardware of firmware-level. first, tag selects randomly the channel of reader and reader need the method which can change the channel of tags. second, reader has the synchronization problem between reader and tag. third, reader has problem that MCU of reader have to operate simultaneously dual interface. To slove this problems, we designed the message and implemented method for tag channel change and the protocol in order to adjust synchronization between reader and tag, Therefore, we compared and analyzed the performance of protocols by experiment. If LP windows size is same, the performance of LP-Combined protocol and AP-Balanced protocol which lower collision probability by its load distribution is more outstanding than single interface protocol performance.

• Journal of the Korea Society of Computer and Information
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• v.15 no.6
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• pp.65-72
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• 2010

In ad-hoc network, the technique to efficiently consume the limited amounts of energy is an important issue since the wireless terminal node is operated on batteries as their energy resource. In order to extend the system lifetime, through a balanced energy consumption, we must delay the situation in which a particular terminal node's energy is depleted and results in system disconnection. Also, the link, which has low reliability due to the mobility of the node, should be avoided considering the key element when setting up the route. The proposed CMLR method in this paper enables to increase the efficiency of energy consumption with a new cost function considering the residue energy of node, error rate of link, and transmission energy consumption. This method is extending the network lifetime and increasing the energy efficiency by compromising the value between the minimization of the transmission energy consumption and maximization of the node's lifetime. Through the simulations the proposed CMLR algorithm was verified by showing better performance over the conventional methods in terms of network lifetime and path efficiency.