• Journal of KIISE
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• v.44 no.7
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• pp.703-709
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• 2017

Outsourcing databases is to offload storage and computationally intensive tasks to the third party server. Therefore, data owners can manage big data, and handle queries from clients, without building a costly infrastructure. However, because of the insecurity of network systems, the third-party server may be untrusted, thus the query results from the server may be tampered with. This problem has motivated significant research efforts on authenticating various queries such as range query, kNN query, function query, etc. Although aggregation queries play a key role in analyzing big data, authenticating aggregation queries has not been extensively studied, and the previous works are not efficient for data with high dimension or a large number of distinct values. In this paper, we propose the AMR-tree that is a data structure, applied to authenticate aggregation queries. We also propose an efficient proof construction method and a verification method with the AMR-tree. Furthermore, we validate the performance of the proposed algorithm by conducting various experiments through changing parameters such as the number of distinct values, the number of records, and the dimension of data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.2952-2971
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• 2016

Outsourcing jobs to a public cloud is a cost-effective way to address the problem of satisfying the peak resource demand when the local cloud has insufficient resources. In this paper, we studied the management of deadline-constrained bag-of-tasks jobs on hybrid clouds. We presented a binary nonlinear programming (BNP) problem to model the hybrid cloud management which minimizes rent cost from the public cloud while completes the jobs within their respective deadlines. To solve this BNP problem in polynomial time, we proposed a heuristic algorithm. The main idea is assigning the task closest to its deadline to current core until the core cannot finish any task within its deadline. When there is no available core, the algorithm adds an available physical machine (PM) with most capacity or rents a new virtual machine (VM) with highest cost-performance ratio. As there may be a workload imbalance between/among cores on a PM/VM after task assigning, we propose a task reassigning algorithm to balance them. Extensive experimental results show that our heuristic algorithm saves 16.2%-76% rent cost and improves 47.3%-182.8% resource utilizations satisfying deadline constraints, compared with first fit decreasing algorithm, and that our task reassigning algorithm improves the makespan of tasks up to 47.6%.

• Journal of the Korea Society of Computer and Information
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• v.11 no.1 s.39
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• pp.223-235
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• 2006

Textile industry of Korea has been assumed advanced textile industry nation's aspects with production system and equipment. But has been descended in the sector of design, brand, recognition comparing with Italy, Japan, England. And products of middle and low price do not have competitiveness against China, South East Asia. The world's textile industry nation has been confronted with Free Trade, and Regional Trade Blocks. New market has been opened with free Trade, but Trade Blocks(NAFTA, EU, APEC etc.) which encourage regional member country's profit maximize made textile export driven nation to consider strategies to cope with. Advanced textile industry nation divided the work among themselves and composed linking system among them which highly valuable products are manufactured at advanced nation and low price products are manufactured by global outsourcing. The purpose of this study is to analyze impact of process which requires to secure international competitiveness into business performance experimentally.

• Information Systems Review
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• v.5 no.2
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• pp.1-21
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• 2003

In this paper, we investigate industrial product intermediary's transformation strategy by exploiting advantages afforded by web based information technologies. Our motivation for this research stems from exploring intermediary's responding strategy to cope with supplier's threatening to disintermediation. From transaction cost perspective, internet can induce both the vertical quasi-integration (electronic hierarchy) and outsourcing (electronic market). Our rationale on directing one of these bi-directional movements is specified on intermediary's value adding on the supply chain. As such, we investigated supply chain performance, IT effects on customer's requirement of channel functions, and channel power structure. Propositions to suggest contingent e-transforming strategic alternatives are logically derived from dyadic nature of supply chain characteristics such as efficiency versus customer services, and supplier dominant versus easy replaceability of suppliers. The contingent e-transformation framework developed from intermediary's perspective is reviewed through longitudinal industry case analysis. Implications from the industry case analysis give us insights for the effectiveness of the framework to combine supply chain characteristics with intermediary's e-transformation.

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.92-100
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• 2015

This study proposes measures to improve management performance of construction projects by re-designing the organizational structures of the Regional Construction Management Administrations of the Ministry of Land, Infrastructure and Transport. The re-designing measures are derived based on the three measures which were established by analyses on status of the Regional Construction Management Administrations, requirements from the current organizational structure, and domestic/overseas examples; the measures are: 1) organizational integration and scope expansion, 2) structural re-organization according to construction projects, and 3) building a knowledge management structure. In order to realize the re-designing measures, sixteen tasks are derived; a milestone is established according to importance, feasibility and lead-lag relationships of these tasks. If these tasks are to be carried out successfully, the management performance of the Regional Construction Management Administrations of the Ministry of Land, Infrastructure and Transport will be expected to improve. Ultimately, the Regional Construction Management Administrations can reduce cost and improve the quality of public service by outsourcing the non-core competence tasks and by concentrating on the construction management for the new infrastructure projects.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.9
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• pp.243-250
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• 2021

Recently, with the development of cloud computing, interest in database outsourcing is increasing. However, when the database is outsourced, there is a problem in that the information of the data owner is exposed to internal and external attackers. Therefore, in this paper, we propose a parallel range query processing algorithm that supports privacy protection. The proposed algorithm uses the Paillier encryption system to support data protection, query protection, and access pattern protection. To reduce the operation cost of a checking protocol (SRO) for overlapping regions in the existing algorithm, the efficiency of the SRO protocol is improved through a garbled circuit. The proposed parallel range query processing algorithm is largely composed of two steps. It consists of a parallel kd-tree search step that searches the kd-tree in parallel and safely extracts the data of the leaf node including the query, and a parallel data search step through multiple threads for retrieving the data included in the query area. On the other hand, the proposed algorithm provides high query processing performance through parallelization of secure protocols and index search. We show that the performance of the proposed parallel range query processing algorithm increases in proportion to the number of threads and the proposed algorithm shows performance improvement by about 5 times compared with the existing algorithm.

• Journal of KIISE
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• v.43 no.12
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• pp.1437-1457
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• 2016

In outsourced databases, the cloud provides an authorized user with querying services on the outsourced database. However, sensitive data, such as financial or medical records, should be encrypted before being outsourced to the cloud. Meanwhile, k-Nearest Neighbor (kNN) query is the typical query type which is widely used in many fields and the result of the kNN query is closely related to the interest and preference of the user. Therefore, studies on secure kNN query processing algorithms that preserve both the data privacy and the query privacy have been proposed. However, existing algorithms either suffer from high computation cost or leak data access patterns because retrieved index nodes and query results are disclosed. To solve these problems, in this paper we propose a new kNN query processing algorithm on the encrypted database. Our algorithm preserves both data privacy and query privacy. It also hides data access patterns while supporting efficient query processing. To achieve this, we devise an encrypted index search scheme which can perform data filtering without revealing data access patterns. Through the performance analysis, we verify that our proposed algorithm shows better performance than the existing algorithms in terms of query processing times.

• International Commerce and Information Review
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• v.14 no.3
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• pp.281-306
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• 2012

Global competition has resulted in companies' expectations to heighten competitiveness and enhance customer service through ownership companies' reduced investment on logistics costs, in turn focusing on the development of core competence, in addition to logistics companies' increased tendencies to satisfy customers' needs and requirements through logistics outsourcing. However, a partial perspective of the logistics contract exists due to its flexible characteristic in order to act accordingly in times of sudden changes and uncertainty. Therefore, this study is designed to test through a survey the standard of desired format of logistics contract in comparison to the currently existing format based on the results of researcher's previous study on the specific clauses in the logistics contract and its effect on the logistics outcome. A hypothesis has been designed to test the differences of perspective between two test groups, and a t-test &IPA (Importance-Performance Analysis) was performed. As a result, firstly, there was a significant difference of perspective between the ownership companies and logistics companies when dealing with the logistics contract; secondly, a significant difference of perspective was also expressed between the two groups on how to guide and re-direct the present standard of logistics contract. In addition, the two groups also showed a difference of expectations between the current and future service standard. Therefore, this study is designed to specify the difference of perspective and expectations between the ownership companies and the logistics companies in order to provide a gateway for the two groups in order to further develop and enhance the field of logistics.

• Journal of Korea Technology Innovation Society
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• v.12 no.2
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• pp.335-359
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• 2009

This study explores the IT governance structures of the Korean conglomerates. It investigates IT organization structures, decision making frameworks and processes, communication channels, implementation mechanisms, and performance evaluation methods around IT activities of the Korean conglomerates by analyzing four different cases. The results show that all of the conglomerates have an IT service firms as one of their subsidiaries, and all the subsidiaries in the conglomerates outsource their IT divisions to the IT service firms, The client firms in the conglomerates operate IT strategy and planning teams to coordinate their IT activities with their outsourcing partners. The IT governance archetype of the Korean conglomerates is found to be "business monarchy" because the client firms mostly make IT decisions. However, the IT service firms provide the information of IT trends and solutions to their clients, so the IT governance archetype of input framework for IT decisions can be "IT monarchy". In addition, the conglomerate which has the more centralized IT governance architecture appears to prefer the more integrated implementation mechanisms for IT decisions. The results of this study are expected to be used as a benchmarking model for the organizations which try to develop an effective IT governance structure.

• International Commerce and Information Review
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• v.14 no.2
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• pp.411-443
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• 2012

The Changes in management environment in SMEs such as rapid development of information communication technology, worldwide expansion of FTAs, enlargement of global outsourcing, etc have changed various aspects in industry-academy or industry-academy-government cooperation. It has been away from the cooperation focused on research and development and industrial training, and advanced to the cooperation focused on the business fields and practices where the executive ability and professionalism are required to commercialize major products of local SMEs. Compared with the existing model, the new model of industry-academy-government cooperation can provide effective and customized supports to local SMEs and expect better performance than ever before through the choice and focus. However, the existing support programs of government and related organizations are just top-down pattern to SMEs. In addition to the development of industrial technology, education and training for labor force and knowledge interchange between industry and university, the new cooperation model would also provide practical tasks such as enhancement of business competences and abilities to cultivate foreign markets. This study deals with Gyeongbuk PRIDE Products support project that is the new model of industry-academy-government cooperation and evaluates the effectiveness of this support project by empirically analyzing the survey results from the target SMEs.