• 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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.5
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• pp.1105-1119
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• 2016

Android includes SEAndroid as a core security feature. SELinux is applied to Android OS as a SEAndroid, because there exists structural differences between Linux and Android. Since the security of SEAndroid depends on the reliable policy if the policy is tampered by the attacker, the serious security problems can be occurred. So we must protect policies which are the most important thing in SEAndoroid. In this paper, we analyze the process of SEAndroid policy updating to find out vulnerabilities and study the attack points on policy tampering. And we propose the SPPA to detect whether the policy is modified by an attacker. Moreover, we prove the performance and the effect of our proposed method on mobile device.

• Korean Journal of Social Welfare
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• v.59 no.3
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• pp.229-252
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• 2007

Traditional quantitative approaches to comparative social policy research in welfare state have mostly focused on cross-national variations in social policy. More recently, they have attempted to account for disparities in the local provision of social policy. However, heavily relying on traditional theories of welfare state development (e.g., industrialism theory, power resource approach, and state-centric thesis), most of them seem to have explained the local variation from a central or national perspective, thereby completely ignoring the local perspective. Furthermore, their theoretical bases have been exclusively derived from the social context of post-war era. In tackling these issues, this study aims at localizing and updating the theoretical framework of local welfare policy in the post-industrial age. The framework provided in this study calls for a shift in the theoretical perspective towards more local and new approaches (e.g., new social risks, new public management and intergovernmental relations).

• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.823-832
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• 2021

In Vietnam, tax compliance has become an important goal in the tax reform strategy. In the context of technology 4.0, the application of the electronic tax system is of great significance to small- and medium-sized enterprises (SMEs). The paper explores factors influencing electronic tax compliance of SMEs in Vietnam. Data from 402 SMEs, who are business taxpayers, was selected through a researcher-designed questionnaire survey method. The results indicate that four groups of factors have significant effects on electronic tax compliance among Vietnamese SMEs. These groups include Taxpayer Awareness (TA), Perceived Ease of use (PTE), Vietnamese tax administration (VTA,) and Efficiency of Vietnamese tax policy (VTP). The factor analysis was adopted; Cronbach's alpha coefficients were calculated, exploratory factor analysis (EFA) was used. The findings found that among these four groups, the most influencing factor is taxpayer awareness. It is suggested that the Vietnamese government should pay attention to promote and support SMEs to raise full awareness of tax obligations. This could be done through various methods such as conducting workshops for updating tax policies and short courses to business taxpayers of electronic tax compliance. The study is expected to provide some important implications for policy-makers and practitioners in tax policy reform in Vietnam.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.1
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• pp.145-164
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• 2023

Cloud computing offers a platform that is both adaptable and scalable, making it ideal for outsourcing data for sharing. Various organizations outsource their data on cloud storage servers for availing management and sharing services. When the organizations outsource the data, they lose direct control on the data. This raises the privacy and security concerns. Cryptographic encryption methods can secure the data from the intruders as well as cloud service providers. Data owners may also specify access control policies such that only the users, who satisfy the policies, can access the data. Attribute based access control techniques are more suitable for the cloud environment as they cover large number of users coming from various domains. Multi-authority attribute-based encryption (MA-ABE) technique is one of the propitious attribute based access control technique, which allows data owner to enforce access policies on encrypted data. The main aim of this paper is to comprehensively survey various state-of-the-art MA-ABE schemes to explore different features such as attribute and key management techniques, access policy structure and its expressiveness, revocation of access rights, policy updating techniques, privacy preservation techniques, fast decryption and computation outsourcing, proxy re-encryption etc. Moreover, the paper presents feature-wise comparison of all the pertinent schemes in the field. Finally, some research challenges and directions are summarized that need to be addressed in near future.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3964-3975
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• 2000

There are two policies for maintaining consistency among the multiple processor caches in a multiprocessor system: Write invalidate and Write update. In the write invalidate policy, whenever a processor attempt to write its cached block, it has to invalidate all the same copies of the updated block in the system. As a results of this frequent invalidations, this policy results in high cache miss ratio. On the other hand, the write update policy renew them, instead of invalidating all the same copies. This policy has to transfer the updated contents through interconnection network, whether the updated block is ptivate or not. Therefore the network suffer from heavy transaction traffic. In this paper we present an efficient cache coherence protocol for shared memory multiprocessor system connected by slotted ring. This protocol is based on the write update policy, but the updated contents are transferred only in case of updating the shared block. Otherwise, if the updated block is private, the updated contents are not transferred. We analyze the proposed protocol and enforce simulation to compare it with previous version.

• Journal of Cadastre & Land InformatiX
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• v.45 no.1
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• pp.17-30
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• 2015

Local governments' spatial information policies are very important in that it can increase the relatedness to upper policy regarding the share, openness and converged utilization of spatial information and contribute to voluntary participation and creative uses linked to big data. However, local governments' spatial information policies require enhancement since it need to update framework spatial data, to derive spatial information service and to share the data. In this research, we compared the spatial information policies and related systems of central and local governments, and analyzed the local governments' spatial information policy enforcement plans and the Seoul metropolitan government's utilization survey on 32 spatial information systems. In the result, for the improvement of local governments' spatial policies, on-demand updating of base map using the as built drawings linked to field work departments, securing up-to-date public domain spatial information through the NSDI system, sharing of spatial information based on the spatial information platform and benchmarking of best practices related to the spatial information based policy participation are suggested.

• Journal of Korea Multimedia Society
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• v.2 no.1
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• pp.1-8
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• 1999

To provide information service with time constraints, it is required to support real-time information system for retrieval and update of distributed information. In this paper, we propose an information retrieval system model for internet. We design and implement a Domain Administration-Oriented search engine for the regional information network. Accordingly, an intelligent robot gathering and updating distributed information is implemented. And, in order to improves the performance of the system, a realtime robot control policy based on the loads of network and web server is proposed.

• Health Policy and Management
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• v.8 no.2
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• pp.76-87
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• 1998

This study analyzed the effect of foreign currency exchange rate on the increasing rate of medical care cost by items of fee schedule of Korean Medical Insurance. This study uses the data of cost analysis including cost of imported goods and the data of for a university hospital National Federation's Medical Insurance for a trend of claim. The method of cost analysis is as same as that used in the study of the development of Korean RBRVS(Resource Based Relative Valus Scale). The main findings of this study are as follows; 1. The proportion of imported goods in cost related to Medical Insurance fee schedule is 7.93%, and in case of substitution of available domestic goods 6.96%. 2. If foreign currency exchange rate changes from 800wen per $1 to 1,300won, the affecting rate of Medical Insurance fee schedules is 5.00%. If the imported goods will be substituted with available domestic goods, the rate 4.35%. Our results can be used a data for updating Medical Insurance fee schedule. But this result is limited to be generalized, because this study used the cost analysis for a university hospital.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2394-2406
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• 2016

ABE has become an effective tool for data protection in cloud computing. However, since users possessing the same attributes share the same private keys, there exist some malicious users exposing their private keys deliberately for illegal data sharing without being detected, which will threaten the security of the cloud system. Such issues remain in many current ABE schemes since the private keys are rarely associated with any user specific identifiers. In order to achieve user accountability as well as provide key exposure protection, in this paper, we propose a key-insulated ciphertext policy attribute based encryption with key exposure accountability (KI-CPABE-KEA). In our scheme, data receiver can decrypt the ciphertext if the attributes he owns match with the self-centric policy which is set by the data owner. Besides, a unique identifier is embedded into each user's private key. If a malicious user exposes his private key for illegal data sharing, his identity can be exactly pinpointed by system manager. The key-insulation mechanism guarantees forward and backward security when key exposure happens as well as provides efficient key updating for users in the cloud system. The higher efficiency with proved security make our KI-CPABE-KEA more appropriate for secure data sharing in cloud computing.