• The KIPS Transactions:PartD
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• v.9D no.2
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• pp.235-242
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• 2002

We propose an advanced transaction scheduling protocol for concurrency control of multilevel secure databases in wireless mobile network environment. Wireless communication is characterized by frequent spurious disconnections. So short-lived transaction must quickly access database without any delay by long-lived one. We adapted two-phase locking protocol, namely traditional syntax-oriented serializability notions, to multilevel secure databases in wireless mobile network environment. Altruistic locking, as an advanced protocol, has attempted to reduce delay effect associated with lock release moment by use of the idea of donation. An improved form of a1truism has also been deployed for extended a1truistic locking. This is in a way that scope of data to he early released is enlarged to include even data initially not intended to be donated. Our protocol is based on extended altruistic locking, but a new method, namely bi-directional donation locking for multilevel secure databases (MLBiDL), is additionally used in order to satisfy security requirements and concurrency. We showed the Simulation experiments that MLBiDL outperforms the other locking protocols in terms of the degree of throughput and average waiting time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.235-246
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• 2009

The number of industry wireless networks based on IEEE 802.11 WLAN technology deployed in large outdoor work sites, such as freight container terminal, is increasing these days. Wider service coverage, frequent movements of stations and high requirement on service reliability are main characteristics of these networks compared to the conventional IEEE 802.11 networks used in home, office and school. While the importance of these networks Bets higher, we can hardly find previous studies including concrete analysis on these networks based on actual experiments. We carried out several field experiments at a freight container terminal to analyze its IEEE 802.11 network and found out some problematic situations, such as over 50% retransmission rates and frequent disruption of communication link while a station is moving. We explain why these problematic situations happen and suggest some solutions, such as application of mesh technology, smart handoff based on location and movement pattern and adjustment of signal strength and channel allocation. Methods and tools used in the experiments are also detailed in the paper which may be helpful for similar future studies.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.42-50
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• 2008

Unlike a cellular network, a mobile ad hoc network(MANET) is constructed only by mobile nodes without access point. Mobile nodes in MANET operate with scarce resources and restricted battery. If battery of intermediate node is exhausted, overall network might be diverged. Therefore, power-aware is really important. An on-demand multipath routing protocol which is proposed to compensate for shortcoming of on-demand single path routing protocol can reduce mute discovery overhead because route discovery starts only when all routes are disconnected. AOMDV(Ad hoc On-demand Multipath Distance Vector) which is on-demand multipath routing protocol based on AODV, reduces 40% of route discovery frequency. However, AOMDV have none of power-aware. So AOMDV have problem that route discovery for power exhaustion is not reduced at all. This paper proposes new power-aware path selection algorithm for AOMDV and scheme that broadcast REER packets when mobile node's battery can be gone. Performance comparison of proposed algorithm with AOMDV using ns-2 simulator shows that route discovery of proposed algorithm is reduced maximally 36.57% than AOMDV's.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.166-170
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• 2001

Rubinstein-Tabyi syndrome(RTS) is a congenital multisystem dysmorphic syndrome with many non-specific features, making diagnosis occasionally difficult. The major features of this syndrome include mental retardation, characteristic facial appearance, short stature, microcephaly, and broad thumbs and halluces. This syndrome was first described by Rubinstein and Tabyi in 1963, and many studies have been continued about this syndrome, but specific pathogenesis of the Rubinstein-Tabyi syndrome phenotype is still not clear. High arched palate, micrognathia and multiple caries etc have been reported in Rubinstein-Tabyi syndrome. In this report, a 6-year and 5-month-old boy visited at our department due to multiple dental caries, who showed broad thumbs, mental and physical development retardation, and characteristic facial appearance including both ptosis and ear deformity. This patient was diagnosed as a Rubinstein-Tabyi syndrome, and treated the multiple dental caries under general anesthesia. This study was aimed to observe the relationship between medical and dental characteristics.

• Korean Journal of Social Welfare
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• v.57 no.1
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• pp.31-60
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• 2005

This study was performed to analyze empowerment process of the disabled. Participants were 11 disabled college students and they were individually face-to-face in-depth interviewed until data were saturated. This study used the grounded theory approach based on Strauss and Corbin(1998). With the qualitative constant comparative analysis, 105 concepts, 22 subcategories, and 12 categories were generated. In the axial coding, a paradigm model was proposed as follows: The central phenomenon of the empowerment process of the disabled adolescents was 'Rising from the Limits'. The causal conditions were 'Just living' and 'realizing disabilities'. The contextual conditions were 'Being excluded', 'But wishing', and 'Breaking down'. The intervening conditions were 'Without giving up' and 'Taking support'. The action/interaction strategies were 'Grasping own lifestyle' and 'Being proactive'. The consequences were 'Acquiring the self-control', 'Getting generosity', and 'Participating in society'. In the selective coding, the core category was 'to live together stately with grasping own lifestyle pro-actively as the disabled'. Based on the core category, three types and 4 stages of the empowerment process of the disabled adolescents were found. The types were 'Social change oriented type', 'Self-development oriented type', and 'Passive effort oriented type' and the stages took 'Isolation stage', 'Rising stage', 'Mastering stage' and 'Stately being together stage'. In particular, this process had the circulation structure of which these 4 stages are not terminated, and developed and repeated. In conclusion, these results convey to us the understanding and knowledge about empowerment process of the disabled as their healthy -whole and unique- development process. And some implications and suggestions for the social work services and theories about the disabled focusing on the pre-adulthood period.

• Korean Journal of Social Welfare
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• v.54
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• pp.99-121
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• 2003

The purpose of this study is to explore the process that youths get involved in delinquent behavior after runaway. The experiences of runaway youths are studied interpretively, so that interactive features between situations and the youths are revealed. In this way, it is expected that directions in social services to prevent and intervene with delinquent behaviors of runaway youths can be suggested. Eleven youths who have experienced running-away participated in the in-depth interviews. Their narratives are interpreted through the procedures of interpretive interactionism by Denzin(1989). Five phases of the delinquency process have been discovered: Using personal resources, getting help from new relationships, exploring alternatives to survive, learning delinquent way of living, and living independently through delinquency. Interpreted contextually, it has been founded that delinquency is a behavior to survive and a developmental process on the street, taking place in a situation of blocked communication, nevertheless within people's networks. Thus, it is suggested that the problem of runaways are not to be treated narrowly as responsibilities of the youths themselves or their families, but to be approached from the viewpoint of providing social service systems that work as a safety network and offer alternatives for the youths to survive, to resolve their troubles, and to keep healthy lives.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.2
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• pp.45-60
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• 2014

In recent year's we have seen that due to education and social position there has been a significant increase in the number of women engaging in entrepreneurial activities. Concurrently research into the activities of women currently engaged in entrepreneurial activities has increased. This research has focused on the individuals themselves, their motivations and the performance of their ventures but there is not enough systematic research on the subject. Therefore it is necessary expand the criteria of the current research to examine every aspect of how these emergent entrepreneurs operate and to provide others with the same goals the appropriate skills and knowledge needed to succeed. This study wants to identify and evaluate the psychological, environmental and personal characteristics that these women possess and to assess the impact these factors have on the level of their success. This study will focus on those women who were empirical in their methods as this lends itself better to a detailed systematic analysis. It will examine the concept of entrepreneurial self-efficacy with regard to how they searched, planned, marshaled and implemented steps to influence the environmental and personal factors that affected them. In addition the searching phase of entrepreneurial self-efficacy directly influences entrepreneurial motivation and thus performance. The results of this study will suggest that as Korean women's interest in entrepreneurship grows it will have wide reaching theoretical implications and affect the direction of the policy that supports it.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.192-204
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• 2013

Fish community structure and inhabit status of endangered fish species were investigated during April to November 2011 in Baebong Stream, Gangwon do, Korea. The number of fish species inhabiting the upper section (Stations 1~3, 5) was 14 and the stream bottoms were mostly composed of cobbles and boulders (Aa-type). Meanwhile, the number of fish species inhabiting the lower section (Stations 4, 6, 7) was 26 and the stream bottoms were mostly composed of pebbles, cobles and sand (Bb-type). A total of 26 species belonging to ten families were found in the stream during the survey period. The dominant and subdominant species were Rhynchocypris steindachneri (31.1%) and Squalidus multimaculatus (13.3%), respectively, and others such as Pungitius kaibarae (11.0%), Zacco koreanus (7.8%), Misgurnus anguillicaudatus (7.0%), Iksookimia pacifica (5.5%) and Z. platypus (5.3%) were followed in the order. Four species of Squalidus multimaculatus, Z. koreanus, I. pacifica and Liobagrus andersoni were endemic to Korea. And, Lethenteron japonica, L. reissneri, Pungitius sinensis and Cottus hangiongensis were endangered fish species in this stream. Oncorhynchus keta, L. japonica and Tribolodon hakonensis were anadromous species, and Plecoglossus altivelis was an amphidromous species. The similarity index based on species composition and abundance clearly divided the fish community structure of the Baebong Stream into two sections fragmented by a weir installed into the stream. It is necessary to install a fish ways on the weirs for a fish migration and movements.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.48-56
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• 2012

One kind of crowdsourcing techniques which allow drivers to collect and provide traffic information using smartphones and applications is being introduced to ITS system as well. The introduction of crowdsourcing techniques requires changes in the existing ITS based on Insourcing which provide traffic information generated by detectors through VMS. ITS Information have had two problems, one is the high cost and the other is an interrupted service. Experts expect crowdsourcing technique which is created SNS, will overcome problems of ITS. But, there are not many examples and research results. Crowdsourcing technique was utilized in Jeju ATMS project to install ITS on the coastal round roads around Jeju since ITS to install point detectors turned out to be non-economic method in case of the coastal round roads with low traffic volume. However, there existed links in which traffic information cannot be generated as there were no smartphone users (crowds) even in the cost-effective crowdsourcing techniques, which indicates the fact that the crowdsourcing method is suitable for urban roads with many smartphone users, but not for local minor roads. On the contrary, insourcing-based ITS is considered to be non-economic method in applying to all roads in the city, but it can be effectively utilized in the local minor roads. Accordingly, Inter-sourcing based ITS operating system in which insourcing is connected with crowdsourcing was suggested in this study.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.5
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• pp.232-242
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• 2002

In a MPLS(Multiprotocol Label Switching) network, it is important to reduce the number of labels and LSP(Lable Switched Path)s for network resource management. MTP(Multipoint-to-Point) LSP can be used to solve this problem. In consideration of traffic engineering, MTP LSP must be chosen to enhance the availability of network and link utilization. Also, a fast mechanism to setup MTP LSPs is required for rerouting capability against link failure. In this paper, we propose a fast MTP LSP traffic engineering of multipath MTP LSP by using a mapping of a MTP LSP upon Diffserv PHBs(Per Hop Behavior) in a Diffserv-capable MPLS network. In the proposed traffic engineering, we determine multiple MTP LSPs in a hierarchical manner according to the characteristics of different services. By using Monte-Carlo method for traffic load balancing process, it provides fast rerouting capability in case of frequent link failure across large network. Out method produces to be nearly optimal within reasonable run-times. It's time complexity is in O( Cn$^2$logn) as conventional multipath routing and it is much faster than Linear Programming approach. Simulation results show that the proposed traffic engineering can be controlled effectively in an administrative manner and enhance the availability of network in comparison with conventional multipath routing.