• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.939-946
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• 2012

Recently privacy breaches has been an social issues. If we should encrypt the sensitive information in order to protect the database, the leakage of the personal sensitive data will be reduced for sure. In this paper, we analyzed the existing protection algorithms to protect the personal sensitive data and proposed the combined method using the bucket index method and the bloom filters. Bucket index method applied on tuples data encryption method is the most widely used algorithm. But this method has the disadvantages of the data exposure because of the bucket index value presented. So we proposed the combined data encryption method using bucket index and the bloom filter. Features of the proposed scheme are the improved search performance of data as well as the protection of the data exposure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.371-381
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• 2011

Recently, there are some social issues that personal sensitive data in database were let out. The best method to protect these personal sensitive data is used by the database encryption method. But the encrypting database makes the query difficult. So, there are a lot of study to protect the database and increase the query efficiency as well. In this paper, we analysed recent research trend to protect the sensitive data and propose the combined method using buckets and the bloom filter for the medical database with range property. Compared to bucket index model, the proposed method can increase bucket index value and protect data distribution exposure. We can estimate that this proposed method can improve searching time and efficiency.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.165-171
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• 2019

Engineering and Technology have been influencing a lot in the field of sports. Competitiveness, attributes of sports, have forced not only sports players but sports goods to enhance those performance. Particularly in the field of motorsports, the convergence of sports and technology has long been done to satisfy between performance and safety. In this study, strength analysis was carried with FEM to develop CFRP Laminate(Carbon Fiber Reinforced Plastic Laminate) bucket seat targeted to motorsports and car tuning industries and FIA($F\acute{e}d\acute{e}ration$ Internationale de l'Automobile) regulation was applied to design the racing seat and evaluate its strength. FEM modeling considered the attributes of composites was followed by strength evaluation based on Tsai-Wu failure index were done according to Lay-up sequence and layer numbers. The result showed that the lay-up sequence with stacking angle such as $[0^{\circ}/30^{\circ}/60^{\circ}/90^{\circ}/-30^{\circ}/-60^{\circ}]_4$ with 3mm form core was optimal selection in the field of weight and strength evaluation.

• Journal of the Korean GEO-environmental Society
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• v.20 no.12
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• pp.41-47
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• 2019

This paper deals with the reliability analysis of foundation for an offshore wind turbine system. Reliability analyses were carried out for suction bucket foundation considering the uncertainties in soil and structural parameters. In reliability analysis, the vertical and lateral resistances are defined as base limit states. The case studies were carried out using the preliminarily designed foundations at western-south mainland sea of Korea. From reliability analyses, vertical resistance for free-slip condition has overall lower reliability index, and submerged unit weight and internal friction angle of seabed soil are governing factors in vertical and lateral resistance in this case.

• The KIPS Transactions:PartD
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• v.10D no.7
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• pp.1077-1088
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• 2003

To increase the retrieval performance in spatial database systems, it is required to develop spatial indexing methods considered the spatial locality. The spatial locality is related to the location property of objects. The previous spatial indexing methods are not considered the circular location property that objects will be taken. In this paper, we propose a dynamic spatial index structure called $Cr^*$-tree, and evaluate the performance of the proposed index structure. This is a new spatial index structure considered the circular location property of objects in which a search space is constructed with the circular and linear domains. By the simulation results, the $Cr^*$-tree shows that the number of disk across is low and the bucket utilization is high regardless of object distribution and bucket capacity.

• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.577-582
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• 2011

EMR(Electronic Medical Record) is an emerging technology that is highly-blended between non-IT and IT area. One of methodology to link non-IT and IT area is to construct databases. Nowadays, it supports before and after-treatment for patients and should satisfy all stakeholders such as practitioners, nurses, researchers, administrators and financial department and so on. In accordance with the database maintenance, DAS (Data as Service) model is one solution for outsourcing. However, there are some scalability and strategy issues when we need to plan to use DAS model properly. We constructed three kinds of databases such as plain-text, MS built-in encryption which is in-house model and custom AES (Advanced Encryption Standard) - DAS model scaling from 5K to 2560K records. To perform custom AES-DAS better, we also devised Bucket Index using Bloom Filter. The simulation showed the response times arithmetically increased in the beginning but after a certain threshold, exponentially increased in the end. In conclusion, if the database model is close to in-house model, then vendor technology is a good way to perform and get query response times in a consistent manner. If the model is DAS model, it is easy to outsource the database, however, some technique like Bucket Index enhances its utilization. To get faster query response times, designing database such as consideration of the field type is also important. This study suggests cloud computing would be a next DAS model to satisfy the scalability and the security issues.

• The Transactions of the Korea Information Processing Society
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• v.3 no.1
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• pp.63-76
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• 1996

In this paper, we propose a new dynamic spatial index structure, called PR -file, for handling spatial objects and the modified hierarchical variance which measures the degree of spatial locality at each level. Under the assumption that a multidimensional search space has a circular domain, PR-file uses the modified hierarchical variance for clustering spatially adjacent objects. The insertion and splitting algorithms of PR_file preserve and index which has a low hierarchical variance regardless of object distributions. The simulation result shows that PR- file has a high hit ratio during a retrieval of objects by using an index with low hierarchical variance. And it shows a characteristic that the larger the bucket capacity, the higher the bucket utilization.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.1
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• pp.33-46
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• 2003

A Home Location Register(HLR) database system manages each subscriber's location information, which continuously changes in a cellular network. For this purpose, the HLR database system provides table management, index management, and backup management facilities. In this thesis, we propose using a two-level index method for the mobile directory number(MDN) as a suitable method and a chained bucket hashing method for the electronic serial number(ESN). Both the MDN and the ESN are used as keys in the HLR database system. We also propose an efficient backup method that takes into account the characteristics of HLR database transactions. The retrieval speed and the memory usage of the two-level index method are better than those of the R-tree index method. The insertion and deletion overhead of the chained bucket hashing method is less than that of the modified linear hashing method. In the proposed backup method, we use two kinds of dirty flags in order to solve the performance degradation problem caused by frequent registration-location operations. For a million subscribers, proposed techniques support reduction of memory size(more than 62%), directory operations (2500,000 times), and backup operations(more than 80%) compared with current techniques.

• The Journal of Information Technology and Database
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• v.8 no.2
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• pp.103-114
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• 2001

In this paper, we propose an efficient index mechanism for real-time main memory database systems. Existing main memory index structures based on the tree can effectively support range searches. However, it doesn't guarantee the real-time characteristic because difference between the access time of a node and an average access time can be high. The index structures based on the hash have always a regular random access time on the simple searches and that speed is very fast. However they do not support range searches. To solve such problems, we propose a new index mechanism called Hyper Tree-Hash (Hyper-TH) that combines ECBH (Extendible Chained Bucket Hashing) and T＊-tree. ECBH can be dynamically extended and has a very fast access time. T＊-tree effectively supports the range searches. We show through our experiments that the proposed mechanism outperforms existing other index structures.

• Electronics and Telecommunications Trends
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• v.16 no.6 s.72
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• pp.29-40
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• 2001

본 고에서는 디스크 기반의 정보검색시스템의 성능을 높이는 것을 목표로, 주기억장치 상주형 정보검색시스템에 적합한 주기억장치 기반의 인덱싱 기법을 비교 평가하고자 한다. 인덱스는 인덱스를 구성하는 키의 순서가 유지되는지의 여부에 따라 크게 두 종류로 나눌 수 있는데, 키가 일정한 순서로 유지되는 트리 계열과 키의 순서와 관계없이 무작위로 유지되는 해시 계열로 구분할 수 있다. 트리 계열 인덱스는 일정한 범위가 주어지는 연산을 처리할 때 유용하게 사용될 수 있으며, 해시 계열 인덱스는 특정한 키에 의한 빠른 데이터 접근을 제공한다. 트리 계열 인덱스로는 AVL 트리, B+ 트리, T 트리 등이 있으며, 해시 계열 인덱스로는 체인 버켓 해싱(Chained Bucket Hashing: CBH), 확장 해싱(Extendible Hashing: EH), 선형 해싱(Linear Hashing: LH), 수정된 선형 해싱(Modified Linear Hashing), 다중 디렉토리 해싱(Multi-directory Hashing) 및 확장된 체인 버켓 해싱(Extendible Chained Bucket Hashing: ECBH) 등이 있다.