• International Journal of Computer Science & Network Security
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• v.23 no.1
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• pp.153-163
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• 2023

This study is situated in the context of intelligent transport systems, where in-vehicle devices assist drivers to avoid accidents and therefore improve road safety. The vehicles present in a given area form an ad' hoc network of vehicles called vehicular ad' hoc network. In this type of network, the nodes are mobile vehicles and the messages exchanged are messages to warn about obstacles that may hinder the correct driving. Node mobilities make it impossible for inter-node communication to be end-to-end. Recognizing this characteristic has led to delay-tolerant vehicular networks. Embedded devices have small buffers (memory) to hold messages that a node needs to transmit when no other node is within its visibility range for transmission. The performance of a vehicular delay-tolerant network is closely tied to the successful management of the nodes' transit buffer. In this paper, we propose a message transit buffer management model for nodes in vehicular delay tolerant networks. This model consists in setting up, on the one hand, a policy of dropping messages from the buffer when the buffer is full and must receive a new message. This drop policy is based on the concept of intermediate node to destination, queues and priority class of service. It is also based on the properties of the message (size, weight, number of hops, number of replications, remaining time-to-live, etc.). On the other hand, the model defines the policy for selecting the message to be transmitted. The proposed model was evaluated with the ONE opportunistic network simulator based on a 4000m x 4000m area of downtown Bouaké in Côte d'Ivoire. The map data were imported using the Open Street Map tool. The results obtained show that our model improves the delivery ratio of security alert messages, reduces their delivery delay and network overload compared to the existing model. This improvement in communication within a network of vehicles can contribute to the improvement of road safety.

• Korean Security Journal
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• no.27
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• pp.51-80
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• 2011

I had an interview with some unemployed career staffs who had retired and worked for more than twenty years in order to research impacting elements on reemployment for l retired special security government officials. This interview included an officer and a consultant for supporting employment in order to explore compacting elements on retired security government official's reemployment. Looking over analysis results, first, there is a shortage of reemployment opportunities and information. The job applicant's employment requirements are not in accordance with the company's employment conditions. They don't have enough professional experience necessary for employment. There is no positive employment supporting counterplan or vocational education program in the organization. Second, their insight about finding a job is high for the current employment market condition. The reemployment offices have a very difficult task because job applicants prefer a full-time job which offers long term work and guarantees a social position. Third, it is a huge obstacle to undertake going into various enterprises and fields because they don't have the right mind set and enough preparation for reemployment. Moreover, they would prefer to depend on organization employment support rather than getting a new job by themselves when they don't possess other careers' qualifications. Finally, they know that social networks and personal connections are extremely important in obtaining vocations, but actually have poor social networks and few personal connections. Accordingly, Their organization and related persons need to reflect on analysis results about impacting elements on reemployment for retired special security government officials.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.21 no.4
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• pp.33-48
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• 2010

The study aimed to identify current situations of Korean church libraries. The results from 22 church libraries are investigated in terms of some factors such as material organization, quantity of materials, facilities, staffs, budgets, public services, users and classification systems. Current libraries are very small in its facility, quantity of the materials and the budget, and lack of the full-time librarian. Recently, children's libraries are established among small churches, and their budgets and public services are stable. Suggestions for revitalizing the church libraries are made: the pastor's understanding of the significance of church library for missions' sake, establishment of more church libraries, acquisitions of various non-book materials, budget security, necessity for a full-time librarian, provision of various types of services and cooperations among church libraries.

• Bulletin of the Korean Mathematical Society
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• v.46 no.4
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• pp.743-769
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• 2009

An ID-based DNF signature scheme is an ID-based signature scheme with an access structure which is expressed as a disjunctive normal form (DNF) with literals of signer identities. ID-based DNF signature schemes are useful to achieve not only signer-privacy but also a multi-user access control. In this paper, we formally define a notion of a (non-interactive) ID-based DNF signature and propose the first noninteractive ID-based DNF signature schemes that are secure under the computational Diffie-Hellman and subgroup decision assumptions. Our first scheme uses random oracles, and our second one is designed without random oracles. To construct the second one, we use a novel technique that converts a non-interactive witness indistinguishable proof system of encryption of one bit into a corresponding proof system of encryption of a bit-string. This technique may be of independent interest. The second scheme straightforwardly yields the first ID-based ring signature that achieves anonymity against full key exposure without random oracles. We finally present two extensions of the proposed ID-based DNF signature schemes to support multiple KGCs and different messages.

• Korean Security Journal
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• no.5
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• pp.309-325
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• 2002

It was because mankind could use the fire that we have been civilized. creating a brilliant culture and developing an industrial society. While fire is very useful to our life, the number of the victims of fire continues to increase, This study suggests the ways to rescue the people safely when they are subject to a fire in a high-rise building. To this end, the concept of fire is reviewed. Fire breaks out when the conditions for congestion are met, and therefore. if any of the conditions can be blocked, the fire will be extinguished. In other words. the knowledge of such conditions will greatly help the fire fighters to rescue the people, and so. such conditions for congestion as flammable, heat, oxygen and chain reaction are examined. In addition, the effects of such by-products of fire as heat and smoke on human body are reviewed. In order to rescue the people more safely, the fire fighters are requested to review the situation and design a rescue strategy before being engaged in a full-scale rescue activity. This study discusses various rescue methods using such passages or equipments as stair case, double ladder, special fire fighting vehicle, elevator, jumar, rope, helicopter, etc. In conclusion. since it is more difficult to rescue the people from a high-rise building than from the ground, it is essential to design a rescue program not after fire but before it and thereby, minimize the number of victims.

• Journal of Korean Society of societal Security
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• v.1 no.4
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• pp.51-56
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• 2008

Because of our country's climate that has the 50% of the annual precipitation in summer, annually a lot of bridges on the roads are broken in this season. So, we need an accelerated bridge construction method that complete to repair the roads. This paper introduces the Hangae 2 bridge, prefabricated bridge using full depth precast deck panels and new types of PSC girders. The Hangae 2 bridge located in lnje-gun, kangwon-do. This is a good example of the accelerated bridge construction method for recovery of flood damaged road. The PSC girder bridge system introduced in this paper is a rapid construction method for bridge that can reduce the term of works over 50%.

• Korean Security Journal
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• no.1
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• pp.321-350
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• 1997

This thesis is an attempt to find out ways and means needed to improve the disaster management system in Korea(Chap. Ⅰ). For this purpose, I have first reviewed various crisis management systems of foreign countries such as the United States, England and Japan(Chap. Ⅱ), and also reviewed that of our own country(Chap. Ⅲ). All of us knows that our disaster management system has been reestablished through the enactment of the Disaster Management Act of 1995 and the full revision of Natural Harzards Management Act of 1995 after a series of catastrophic man-made disasters since 1993. I took a general survey of the contents and characteristics of the newly made Disaster Management Act(Chap. Ⅳ), and Finally, as a conclusion of this research(Chap. V), I indicated a few disputed points on the Disaster Management Act and suggested several alternatives to improve our crisis management system. The alternatives suggested are as follows (1) Reinforcement of prevention-centered policy and expansion of investment (2) Specialization of the crisis management man-power and securing the rescue equipment (3) Arrangement of the various lessons on crisis and reinforcement of educational training against the disasters (4) Building the cooperative systems between the civil organizations (5) An opinion towards the issues on the unifying the law systems and reorganizaing the new independent institution for the crisis management

• Korean Journal of Social Welfare
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• v.46
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• pp.178-209
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• 2001

This paper aims to provide a critical assesment of Conservatives's and new Labour's social assistance reforms in the U.K. and their differential impacts on low income groups. During the period of 18 years in power, the Conservative governments enforced benefit recipients being capable of work to be out of benefits and to get into work. They employed not only 'carrots' to encourage beneficiaries being capable of work to have full-time work, but also 'sticks' to discourage them to depend on benefits. The reforms under the Conservative governments were closer to the workfare model. The new Labour government has continued to emphasize work regarding social security reform. It has raised 'from welfare to work' as the main reform objective. However, it has not necessarily focused on 'carrots and sticks' in order to get beneficiaries into work. Instead, the new Labour government has put its priority regarding social assistance reform on human capital development in order to develop the capability of beneficiaries for work. Britain under the new Labour government seems to be moving from workfare to activation model. These differentials between the Conservative governments and the new Labour government regarding social assistance reforms bring about the different policy outcomes. Under the Conservative government, social assistance programmes were prone to strengthen the state's control over benefit recipients and to increase stigma to them. Punitive, demeaning, stigmatising programmes of work and unending job search activities harm the bases of self-respect. On the contrary, the activation programmes under the new Labour government has contributed positively to both socially significant participation and autonomy of beneficiaries.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2646-2659
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• 2017

Equipped with the advantages of flexible access control and fine-grained authentication, attribute based signcryption is diffusely designed for security preservation in many scenarios. However, realizing efficient key evolution and reducing the calculation costs are two challenges which should be given full consideration in attribute based cryptosystem. In this paper, we present a key-policy attribute based signcryption scheme (KP-ABSC) with delegated computation and efficient key updating. In our scheme, an access structure is embedded into user's private key, while ciphertexts corresponds a target attribute set. Only the two are matched can a user decrypt and verify the ciphertexts. When the access privileges have to be altered or key exposure happens, the system will evolve into the next time slice to preserve the forward security. What's more, data receivers can delegate most of the de-signcryption task to data server, which can reduce the calculation on client's side. By performance analysis, our scheme is shown to be secure and more efficient, which makes it a promising method for data protection in data outsourcing systems.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.811-822
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• 2020

This study investigates the gender differences in determinants of customers' satisfaction when purchasing online beauty and cosmetics products in Vietnamese market. To do so, we construct a data set via online survey of 419 Vietnamese customers including both males and females, and examine such sample using t-tests and multiple regressions. Our regression model is constructed based on our five-construct model including online shopping experience, customer service, external incentives, security and privacy, and personal characteristics. The t-tests results reveal that the mean difference of customer satisfaction (negative coefficient) between the two groups of customers (females and males) is statistically significant. This suggests that the purchasing satisfaction of male customers is significantly higher than that of their female counterparts. Similarly, we also find that male customers are more satisfied with their online shopping experience, customer service and external incentives offered by the online sellers than female peers. Furthermore, regression results for full sample show that, on average, the online shopping experience, customer service and external incentives are significantly and positively related to customer satisfaction. Yet, such positive effect of customer service on customer satisfaction is more likely for males while females' satisfaction is more positively influenced by security and privacy.