• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2285-2301
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• 2012

Peer-to-Peer (P2P) networks are becoming more and more popular in video content delivery services, such as Video on Demand (VoD). Scalability feature of P2P allows a higher number of simultaneous users at a given server load and bandwidth to use stream service. However, the quality of service (QoS) in these networks is difficult to be guaranteed because of the free-riding problem that nodes download the recourses while never uploading recourses, which degrades the performance of P2P VoD networks. In this paper, a distributed trust model is designed to reduce node's free-riding phenomenon in P2P VoD networks. In this model, the P2P network is abstracted to be a super node hierarchical structure to monitor the reputation of nodes. In order to calculate the reputation of nodes, the Hidden Markov Model (HMM) is introduced in this paper. Besides, a distinction algorithm is proposed to distinguish the free-riders and malicious nodes. The free-riders are the nodes which have a low frequency to free-ride. And the malicious nodes have a high frequency to free-ride. The distinction algorithm takes different measures to response to the request of these two kinds of free-riders. The simulation results demonstrate that this proposed trust model can improve QoS effectively in P2P VoD networks.

• Land and Housing Review
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• v.3 no.3
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• pp.241-248
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• 2012

Although infrastructure cost comprises the great proportion of residential development cost, all of it tends to be borne by land developers which develop large area. This brings about free-riding by adjacent small development or built-up area, followed by the equity problem in terms of infrastructure development cost sharing and the privatization of development gain. This study aims to establish the method to analyze free-riding on the transportation infrastructure(roads) and investigate empirically how much the free-riding occurs. It sets several development scenarios to calculate the part generated by Bucheon Sangdong district, the case area of this study, of all the traffic flow on the roads. The Network analysis is used to estimate the proportion, by development scenarios, of traffic flow, travel time, and travel cost. As a result, the developer of Bucheon Sangdong district is responsible for 83% of the construction cost of selected roads. The methodology and empirical result of this study would contribute to determine who are liable for the infrastructure facilitation and to estimate how much of the cost the obligators have to share.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.327-330
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• 2006

P2P 파일 공유 시스템은 중앙 서버를 거치지 않고 피어 컴퓨터들 간의 직접적인 자원 공유로 특징지워지는 P2P 기술의 대표적인 응용으로, 사용자는 인터넷을 통해 원하는 파일을 쉽게 검색, 획득, 유포할 수 있다. 그러나 악의적인 사용자가 허위 파일이나 바이러스를 유포할 수 있어, 허위파일로 인한 재전송이 빈번해짐으로써 네트워크 트래픽이 증가하고, 바이러스로 인한 피해가 발행할 수 있다. 또한, 자신의 파일에 대한 공유없이 다른 사용자들의 공유 파일만 다운로드하는 free riding 문제가 발생할 수 있다. 이 논문에서는 사용자의 파일 공유 트랜잭션 정보에 기반한 신뢰 정보를 이용하여 P2P 파일 공유 시스템의 문제점을 보완할 수 있는 시스템을 제안한다. 제안한 시스템에서 중앙 서버는 사용자의 파일 공유 트랜잭션 피드백을 이용하여 사용자 신뢰도를 구하여 허위파일이나 바이러스를 유포하는 악의적인 사용자나 free rider에 대해 시스템 사용을 제한한다. 사용자는 파일 다운로드 시에 중앙 서버로부터 사용자 메타데이터를 수신하여 자신의 선호도를 반영한 파일 신뢰도를 이용함으로써 허위파일이나 바이러스를 다운로드할 위험을 줄인다.

• Management Science and Financial Engineering
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• v.11 no.1
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• pp.25-48
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• 2005

Firms often collaborate on building an infrastructure, which benefits all the firms in the industry, although in unequal magnitudes. Then a difficult and tricky issue is concerned with 'free riding.' Should there be only 'common, i.e., industry-wide' benefits in such collaboration, the literature indicated that the free rider problem is unavoidable, In this paper, however, we suggest that while collaborating, the firm also learns firm-specific knowledge, experience, and know-how, which can be directly utilized for its own internal improvement. That is, the collaboration between firms provides them with not only 'industry-wide,' but also 'firm-specific' benefits, Our analysis shows that if there indeed exist two types of benefits simultaneously, depending on the balance between the two, the free rider problem can be mitigated or even eliminated.

• Journal of Korea Technology Innovation Society
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• v.1 no.2
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• pp.153-164
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• 1998

This study attempts to provide policy makers and other interested parties with policy implications throughout an economic analysis of software sector. Chapter 2 is designed to provide an overview of market characteristics in the software sector. Chapter 3 reviews an overview of the evolution stage of the software industry and the effects these trends have on firm strategies. Chapter 4 reviews the relationships between software economic characteristics and intellectual property rights. Some suggestions are offered in the conclusion, with special attention given to an examination of market characteristics, firm strategies, government policies, and some economic factors.

• Journal of Life Science
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• v.21 no.11
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• pp.1612-1618
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• 2011

The present study was undertaken to analyze the effects of different types of treatment on excess post exercise oxygen consumption (EPOC), flexibility, free radical and antioxidants in women using a horseback riding therapeutic device. Subjects were trained in regular horseback riding exercises for 12 weeks (3 times/wk). The effects of this exercise were examined by means of a single session of horseback riding that lasted for 30 min. 21 women were recruited from a public health center and divided into 3 groups (passive recovery group, passive+massage recovery group, and dynamic recovery group). 3 types of recovery patterns were determined after a single trial of horseback riding exercise. Their flexibility were determined pre-and post-training by Paired T test, and ANOVA were used to analyze the data. The results were as follows: Among the 3 groups, the dynamic recovery group showed the highest levels of EPOC compared to the other groups, and also showed higher levels of anti-oxidants, as did the passive+massage recovery group compared to the passive recovery group. Moreover, horseback riding exercise greatly increased flexibility in the women. In conclusion, regular horseback riding training is recommended to enhance the flexibility of women and dynamic recovery is recommended to enhance EPOC and anti-oxidants after a single bout of exercise. Further study is needed in this area.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.2854-2874
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• 2015

This paper presents a game theoretic approach to analyze the public goods (PGs) allocation in peer-to-peer (p2p) networks. In order to reduce the free-riders and promote the cooperation among peers, we propose an incentive mechanism with cooperation-based game theory. In this paper, we regarded the contributed resources by cooperators as public goods (PGs). We also build the PGs allocation in P2P networks to be the optimization problem, and the optimal solution of PGs allocation satisfies the Bowen-Lindahl-Samuelson equilibrium. Firstly, based on the subscriber mechanism, we analyze the feasibility and prove the validity, which can achieve Nash equilibrium. However, this strategy cannot meet to Bowen-Lindahl-Samuelson equilibrium as the free-riders do not pay with their private goods for consuming the PGs. Secondly, based on the Walker mechanism, we analyze the feasibility and prove the validity for the same allocation problem, which meets to Bowen-Lindahl-Samuelson equilibrium and achieves Pareto efficiency within cooperative game. Simulations show that the proposed walker mechanism can significantly improve the network performance of throughout, and effectively alleviate free-riding problem in P2P networks.

• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.493-498
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• 2005

P2P service is a method that can share various information through direct connection between computer of a person who have information and a Person who have information without server in the Internet and it is getting a lot of popularity by method for free ex change of file. P2P file sharing systems have become popular as a new paradigm for information exchange. Because all users who use service in P2P file sharing system can use shared files of several users freely by equal access privilege, it is happening the 'free rider' that only download shared file of other users without share own files. Although a user share a malicious file including virus, worm or file that have title differing with actuality contents, can use file sharing service without limitation. In this paper, we propose a method that restrict access of 'free rider' that only download using reputation information that indicate reliability of user. Also, we restrict usage ons hared file of other users about users who share harmful file.

• Fire Science and Engineering
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• v.20 no.2 s.62
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• pp.31-43
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• 2006

In Korea, the Emergency Medical Service, EMS is provided by Fire Services with 119 EMS and all the public uses the service for free. Although it appears very successful and is respected nationally, structural problem EMS exist and are worsening. First of all, the "free riding effect" becomes increasingly problematic. Some argue that 30% of the demands is not urgent or emergent. The total number of demands is increasing even without the free riding effect. The Current EMS system itself cannot meet the increasing EMS demand. The medical aspect is so poor that the EMS cannot dispatch a medical specialist to the scene. The cardiac arrest resuscitation rate is only $1.24{\sim}9.9%$, compared to 40% in Boston, MA, USA. But due to the regulations and limitations of the Fire Service organization, it is difficult to secure enough EMS resources. To work out these problems, it needs a structural innovation. To secure enough resources and achieve higher medical performance we should invite the medical sector and the private sector into EMS arena by contracting partnerships with Fire Services and charging a reasonable EMS fee. We found through statistical test that any partnership system is more effective than fire-alone system and most countries around the world have partnership system rather than fire-alone system.

• The Journal of Fisheries Business Administration
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• v.34 no.1
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• pp.115-136
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• 2003

As of late, people who enjoy fishing as a pastime in Korea has dramatically increased on the back of the increased national income and 5-day working system being in place. In the past, people used to fish in inland waters, but fishing on the sea has also shown a steady increase. The expanded fishing community along with increasing types of fishing, however, led to destruction of ecosystem by littering the waters of both inland and sea with wastes and reckless exploitation of fish resources. Fishing activities are usually taking place in inland waters, or on the sea, which is, by definition, a common property, and side effects such as free riding and diseconomy are frequently observed occurring. In other words, everyone can use the property free of charge(except paying fishing lot), and littering the waters with pollutants and wastes stemming from fishing activities is currently rampant. In this context, this paper studies the necessity of introducing fishing license system and its feasibility in Korea from a perspective to improve the national welfare through policy measures based on 'polluter pays principle' to prevent further environmental pollution in the fishing lot and preserve fishery resources. Study shows that introduction of Recreational fishing license system is urgently needed, but it is concluded that it should take more time to implement the system so as to accomodate the differing interests of all parties involved including recreational fishing industry, while strengthening public relation activities to solicit for the people's understanding of the system to be introduced.