• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.1249-1262
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• 2020

Along with the increase of the importance of information used in practice, adversaries tried to take valuable information in diverse ways. The simple and fundamental solution is to encrypt the whole data. Since the cost of encryption is increasing along with the size of data, the cost for securing the data is a burden to a system where the size of the data is not small. For the reason, in some applications where huge data are used for service, service providers do not use any encryption scheme for higher security, which could be a source of trouble. In this work, we introduce a new type of data securing technique named Trapdoor Digital Shredder(TDS) which disintegrates a data to multiple pieces to make it hard to re-construct the original data except the owner of the file who holds some secret keys. The main contribution of the technique is to increase the difficulty in obtaining private information even if an adversary obtains some shredded pieces. To prove the security of our scheme, we first introduce a new security model so called IND-CDA to examine the indistinguishability of shredded pieces. Then, we show that our scheme is secure under IND-CDA model, which implies that an adversary cannot distinguish a subset of shreds of a file from a set of random shreds.

• 정보관리연구
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• 제38권1호
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• pp.59-73
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• 2007

재사용 및 의미공유가 가능한 가공 데이터베이스를 구축하기 위해서는 의미적 메타데이터 관리가 요구된다. 이 연구에서는 가공 데이터를 위한 의미적 데이터 모델링 프로세스를 개발하였다. 이것은 기존의 데이터 모델들과 메타데이터 레지스트리를 다루는 ISO/IEC 11179 표준을 복합한 것이다. 데이터의 의미적 상호운용성을 확보하기 위해서 데이터 요소 이름을 구성하는 객체 클래스 이름과 특성 이름들은 기존의 데이터 모델을 이용해서 식별하고, 데이터 요소의 명명과 명세는 ISO/IEC 11179에 근거해서 이루어진다. 방전가공이라는 기계가공에 실험적으로 적용함으로써 방법론을 설명하였다.

• 한국인터넷방송통신학회논문지
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• 제11권2호
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• pp.63-72
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• 2011

방송 기반의 데이터 전파는 모바일 컴퓨팅 환경에서 보편적으로 받아들여지는 통신 방식이다. 그러나 많은 데이터를 방송해야 할 경우에 방송 채널의 순차성으로 인하여 원하는 데이터를 수신하기까지의 예상 지연시간이 증가한다. 이 대기시간을 줄이기 위하여 본 논문은 다중 채널을 통하여 데이터를 방송하는 문제를 연구한다. 기존의 기법들은 각 채널의 평형 방송을 가정하고 데이터들을 액세스 확률에 근거하여 분할하고 다중 채널에 할당한다. 만일 동일 채널에 할당된 데이터들도 그들의 액세스 확률에 근거하여 방송빈도를 다르게 한다면 성능은 더 향상될 것이다. 이와 같은 관점에서 본 논문은 동일 채널에 할당된 데이터들의 액세스 확률의 차이를 방송 스케줄에 반영할 수 있는 두 단계 동적프로그래밍 기법으로 명명된 새로운 방송 스케줄링 기법을 제안한다.

• Journal of Ship and Ocean Technology
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• 제5권2호
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• pp.1-13
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• 2001

Data in one Product Model for shipbuilding is inevitably referenced and manipulated during each phase of design or production activities, and data or manipulation status naturally varies from the original with the advance of each activities. For Object-Oriented approach, it is hard to identify classes dealing with those variations, and even if once a product model is developed, it might be getting much harder to modify it to cope with a new additional phase of activities. This paper proposes an Instance-Oriented Modeling Method, temporarily named “Concept-Relationship Modeling Approach”, which handles Data structure and Behavior independently of each other in order to resolve the difficulties above.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권6호
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• pp.2761-2781
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• 2018

With the continuous growth of data size and the use of compression technology, data reduction has great research value and practical significance. Aiming at the shortcomings of the existing semantic compression algorithm, this paper is based on the analysis of ItCompress algorithm, and designs a method of bidirectional order selection based on interval partitioning, which named An Optimized Iterative Semantic Compression Algorithm (Optimized ItCompress Algorithm). In order to further improve the speed of the algorithm, we propose a parallel optimization iterative semantic compression algorithm using GPU (POICAG) and an optimized iterative semantic compression algorithm using Spark (DOICAS). A lot of valid experiments are carried out on four kinds of datasets, which fully verified the efficiency of the proposed algorithm.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.445-450
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• 2001

DVD(Digital Versatile Disk) is the data storage media devised to make high storage density and high data input/output possible. Therefore higher rotational speed and better accuracy in optical pick-up are required compared with the existing optical storage device. These operational functional requirements are concerned with abilities of optical storage device. Especially, High rotational speed is deeply concerned with the noise and vibration of optical storage device, is important problem in development of optical storage device so much. This paper propose a new concept ROM media of optical storage device named as Cylindrical ROM media, and evaluate this by means of Axiomatic approach and empirical data.

• Smart Structures and Systems
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• 제10권4_5호
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• pp.393-410
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• 2012

The 610 m high Canton Tower (formerly named Guangzhou New Television Tower) is currently considered as a benchmark problem for structural health monitoring (SHM) of high-rise slender structures. In the benchmark study task I, a set of 24-hour ambient vibration measurement data has been available for the output-only system identification study. In this paper, the vector autoregressive models (ARV) method is adopted in the operational modal analysis (OMA) for this TV tower. The identified natural frequencies, damping ratios and mode shapes are presented and compared with the available results from some other research groups which used different methods, e.g., the data-driven stochastic subspace identification (SSI-DATA) method, the enhanced frequency domain decomposition (EFDD) algorithm, and an improved modal identification method based on NExT-ERA technique. Furthermore, the environmental effects on the estimated modal parameters are also discussed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1173-1176
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• 1996

Multilayer feedforward networks may be applied to identify the deterministic relationship between input and output data. When the results from the network require a high level of assurance, considering of the stochastic relationship between the data may be very important. The variance is one of the useful parameters to represent the stochastic relationship. This paper presents a new algorithm for a multilayer feedforward network to learn the variance of dispersed data without preliminary calculation of variance. In this paper, the network with this learning algorithm is named as a variance learning neural network(VALEAN). Computer simulation examples are utilized for the demonstration and the evaluation of VALEAN.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1996년도 추계학술대회발표논문집; 고려대학교, 서울; 26 Oct. 1996
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• pp.93-95
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• 1996

A replication server is considered to be one of the most effective tools to cope with the problems that may be caused by the complex data replications in distributed database systems. In the distributed environment, locking a table is inevitable and it is the main reason to coerce the system practically. This paper presents an Asynchronous Replicator Scheme (ARS) that basically utilizes the system log as files named differential files to refresh the distributed data files with complicated queries, and that it prevents (normally, huge) base tables from being locked. We take join operations as the complicated queries, not only because the join operation covers almost all the operations, but also because it is one of the most time-consuming and data intensive operations in query processings.

• 한국CDE학회논문집
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• 제20권4호
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• pp.401-411
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• 2015

Cybrid virtual plant concept is defined as a cyber plant mimicking a physical plant by using plant engineering data and sensor data coming from sensors attached to facilities of the physical plant. Cybrid virtual plant is a new concept for plant industry so that plant managers and operators' requirements need to be captured for systematic application of the concept to the plant industry. The paper proposed an architecture of the cybrid virtual plant, and provided requirement analysis results for a specific plant company. A database, named smart-cube repository, for the proposed cybrid virtual plant is also proposed and its conceptual data structure is described.