• Proceedings of the Korea Information Processing Society Conference
• /
• 2015.10a
• /
• pp.730-732
• /
• 2015

데이터 중복 제거 기술은 클라우드 스토리지에 저장되어 있는 중복된 데이터들 중에 하나의 데이터만 저장하는 기술로, 클라우드 스토리지 서비스에서 저장효율을 높이기 위한 핵심적인 기술 중 하나이다. 하지만 아웃소싱된 데이터가 암호화가 되지 않으면 기밀성을 유지하지 못해 프라이버시에 큰 영향을 끼치게 된다. 데이터를 암호화하여 아웃소싱하는 경우에는 암호문의 특성으로 인해 중복 제거 기술이 적용하기 힘든 단점을 가지고 있으며 이를 위해 수렴 암호화를 사용한다. 본 논문에서는 수렴 암호화로 암호화된 데이터에 대해 중복제거 기술을 적용하는 여러 제안모델을 분석하고, 개선방안을 제시한다.

• Journal of Internet Computing and Services
• /
• v.11 no.2
• /
• pp.155-164
• /
• 2010

The purpose of this paper is to propose critical success factors for effectively managing information systems(IS) outsourcing. The survey method was used for this paper, and data from a total 106 companies that were listed greater than $10 million were used for the analysis. To analyze the data, structural equation model was used. The results of this empirical study is summarized as follows. First, both formal control based on contract and informal control based on trust have a positive effect on control level which is a determinant indicator of IS outsourcing performance. Second, management capability such as preparedness capability and relationship capability have a positive effect on formal and informal control mechanism. The findings have important implications for the role of trust and management capability in formal management control.

• 한국IT서비스학회:학술대회논문집
• /
• 2003.11a
• /
• pp.301-308
• /
• 2003

본 연구의 목적은 IT 아웃소싱의 효익을 정성적이고 정량적으로 측정 가능하게 해 주고, 성과를 지속적으로 관리하게 해 주는 IT BSC 기반의 성과측정 프레임웍을 제안하고자 함이다. BSC는 전통적인 재무적 성과측정 방법에 고객, 내부 비즈니스 프로세스, 학습과 성장과 같은 무형의 효익 보완해 준다는 측면을 가지고 있어, IT 성과를 측정하는데 적용되어 왔다. 본 연구는 IT BSC를 통해 비즈니스 전략과 연계한 성과를 측정하기 위해 지표의 도출, 측정 데이터의 수집에서, 분석 보고에 이르는 전 과정을 제시하고 있다. 이는 IT 아웃소싱의 성과를 정량적, 정성적으로 측정하는 것을 가능하게 해 주는 방법론의 제시라는 데 의의가 있다.

• KIPS Transactions on Computer and Communication Systems
• /
• v.6 no.10
• /
• pp.429-436
• /
• 2017

There is a growing tendency to outsource sensitive or important data in cloud computing recently. However, it is very important to protect the privacy of outsourced data. So far, a variety of secure and efficient multi-keyword search schemes have been proposed in cloud computing environment composed of a single data owner and multiple data users. Zhang et. al recently proposed a search protocol based on multi-keyword in cloud computing composed of multiple data owners and data users but their protocol has two problems. One is that the cloud server can illegally infer the relevance between data files by going through the keyword index and user's trapdoor, and the other is that the response for the user's request is delayed because the cloud server has to execute complicated operations as many times as the size of the keyword index. In this paper, we propose an improved multi-keyword based search protocol which protects the privacy of outsourced data under the assumption that the cloud server is completely unreliable. And our experiments show that the proposed protocol is more secure in terms of relevance inference between the data files and has higher efficiency in terms of processing time than Zhang's one.

• KIPS Transactions on Software and Data Engineering
• /
• v.4 no.12
• /
• pp.543-548
• /
• 2015

Recently top-k query processing has been extremely important along with the explosion of data produced by a variety of applications. Top-k queries return the best k results ordered by a user-provided monotone scoring function. As cloud computing service has been getting more popular than ever, a hot attention has been paid to cloud-based data outsourcing in which clients' data are stored and managed by the cloud. The cloud-based data outsourcing, though, exposes a critical secuity concern of sensitive data, resulting in the misuse of unauthorized users. Hence it is essential to encrypt sensitive data before outsourcing the data to the cloud. However, there has been little attention to efficient top-k processing on the encrypted cloud data. In this paper we propose a novel top-k processing algorithm that can efficiently process a large amount of encrypted data in the cloud. The main idea of the algorithm is to prune unpromising intermediate results at the early phase without decrypting the encrypted data by leveraging an order-preserving encrypted technique. Experiment results show that the proposed top-k processing algorithm significantly reduces the overhead of client systems from 10X to 10000X.

• Journal of KIISE
• /
• v.42 no.5
• /
• pp.652-663
• /
• 2015

Due to the popularity of location-based services, the amount of generated spatial data in daily life has been dramatically increasing. Therefore, spatial database outsourcing has become popular for data owners to reduce the spatial database management cost. The most important consideration in database outsourcing is meeting the privacy requirements and guarantying the integrity of the query result. However, most of existing database transformation techniques do not support both of the data privacy and integrity of the query result. To solve this problem, we propose a spatial data transformation scheme that utilizes the shearing transformation with rotation shifting. In addition, we described the attack models to measure the data privacy of database transformation schemes. Finally, we demonstrated through the experimental evaluations that our scheme provides high level of data protection against different kinds of attack models, compared to the existing schemes, while guaranteeing the integrity of the query result sets.

• The Journal of the Korea Contents Association
• /
• v.12 no.1
• /
• pp.275-298
• /
• 2012

Holding conventions and exhibitions are deemed as a highly valued-added services. The conventions and exhibitions industry (CEI) contributes to the development of the region in which the venues are located by creating jobs, boosting the local economics, attracting dollars and increasing tax incomes. At the same time, the international awareness of the region rises after holding an international exhibition or convention. This study investigated the effects of outsourcing services quality that employed by corporations organizing conventions and exhibitions on business performance and customer satisfaction of organizing corporations. It was found that many convention organizing corporations relied on outsourcing services for the most of the process. Given that the staff members of outsourcing companies serve as the major source of services for events, the quality of their services has much effects on the business results of hiring corporations. In this study, major factors influencing the service quality and the importance of the service quality were addressed. And the ideas for effective method for controlling the outsourcing sources were also suggested for hiring corporations and outsourcing companies.

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

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

• Proceedings of the Korea Information Processing Society Conference
• /
• 2016.10a
• /
• pp.226-227
• /
• 2016

클라우드 컴퓨팅 환경에서 사용자 관점에서는 아웃소싱한 데이터의 기밀성 및 무결성을, 클라우드 제공자 입장에서는 저장 공간 및 대역폭 효율을 모두 제공하는 것이 필요하다. 본 논문에서는 이를 동시에 만족시키기 위해 아웃소싱된 데이터의 중복 제거 기법과 클라우드 스토리지에 저장된 데이터 파일의 무결성 검증 기법이 결합된 기법에 대해 분석한다.