• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.4
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• pp.919-943
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• 2019

Distributed ledger technology, which is attracting attention as an emerging technology related to the 4th Industrial Revolution, is implemented as an open source based distributed ledger technology system and widely used for development with various applications (or services), but the security functions provided by the distributed general ledger system are very insufficient. This paper proposes security enhancements for distributed ledger technology systems based on open source. To do so, potential security threats that may occur under running an open source based distributed ledger technology systems are identified and security functional requirements against the security threats identified are provided by analyzing legislation and security certification criteria (ISMS-P). In addition, it proposes a method to implement the security functions required for an open source based distributed ledger technology systems through analysis of security functional components of Common Criteria (CC), an international standard.

• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.71-83
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• 2005

In this paper, we developed the Distributed Programming Developing Tool(DPDT) which can make distributed application program efficiency based on the distributed object group framework supporting group management and dynamic binding for object resources requested from clients on distributed systems. The distributed object group framework we constructed provides not only the group register/withdraw, the access right and the name/property services for server objects from a point of view of group management services, but also dynamic binding, replicated object supporting, load balance, and federation among the object groups from a point of view of the supporting services of distributed application, When developing distributed application, by using our tool, server programming developer implements objects in each server system, next registers the properties to need for service provision to the object group. Client programming developer can also develop client program easily by obtaining the access right for the object or the object group and using the properties of objects with the access right permitted to the client. For providing above application developing environment in this paper. we described the definition of object group, the architecture of the distributed object group framework which our tool supports, and its functionalities, then specified the 3 GUI environments of DPDT implemented for providing efficient interfaces between the distributed object group and distributed applications. Finally, by using the DPDT, we showed the group register/withdraw and the access right grant procedure of objects which are server programs, the developing process of client program, and the executing results of the distributed application developed.

• Annual Conference of KIPS
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• 2018.10a
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• pp.39-42
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• 2018

Log analysis and monitoring have a significant importance in most of the systems. Log management has core importance in applications like distributed applications, cloud based applications, and applications designed for big data. These applications produce a large number of log files which contain essential information. This information can be used for log analytics to understand the relevant patterns from varying log data. However, they need some tools for the purpose of parsing, storing, and visualizing log informations. "Elasticsearch, Logstash, and Kibana"(ELK Stack) is one of the most popular analyzing tools for log management. For the ingestion of log files configuration files have a key importance, as they cover all the services needed to input, process, and output the log files. However, creating configuration files is sometimes very complicated and time consuming in many applications as it requires domain expertise and manual creation. In this paper, an auto configuration module for Logstash is proposed which aims to auto generate the configuration files for Logstash. The primary purpose of this paper is to provide a mechanism, which can be used to auto generate the configuration files for corresponding log files in less time. The proposed module aims to provide an overall efficiency in the log management system.

• Communications for Statistical Applications and Methods
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• v.4 no.2
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• pp.427-434
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• 1997

The purpose of this paper is to discuss distribution-free tests of hypothesis that the random samples are identically distributed against the epidemic alternative. But most tests that have been considered are depended only on specific null distribution. Two nonparametric tests are considered and compared with a likelihood ratio test by the empirical powers.

• Communications for Statistical Applications and Methods
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• v.8 no.3
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• pp.875-883
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• 2001

We derive the asymptotic relative efficiencies in two special cases of Chaudhuri's estimators for the multivariate one sample problem. And we compare those two when observations are independent and identically distributed from a family of spherically symmetric distributions including normal distributions.

• Communications for Statistical Applications and Methods
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• v.19 no.2
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• pp.247-256
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• 2012

In this paper we prove the complete convergence for weighted sums of pairwise negatively quadrant dependent random variables. Some results on identically distributed and negatively associated setting of Liang and Su (1999) are generalized and extended to the pairwise negative quadrant dependence case.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.440-448
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• 1999

본 논문은 객체지향형 분산처리 환경 하에서 오디오나 비디오 등과 같은 실시간(real-time) 스트림(stream) 데이타를 처리하는 데 필요한 소프트웨어 기반구조를 설계하고 구현한 내용을 기술한다. 본 논문에서 제시한 DAViS(Distributed Object Framework supporting Audio/Video Streaming)는, 오디오/비디오 데이타의 처리와 관련된 여러 소프트웨어 구성요소들을 분산객체로 추상화하고, 그 객체들간의 제어정보 교환경로와 오디오/비디오 데이타 전송경로를 서로 분리하여 처리한다. 분산응용프로그램 작성자는 DAViS에서 제공하는 서비스들을 이용하여, 기존의 분산프로그래밍 환경이 제공하는 것과 동일한 수준에서 오디오/비디오 데이타에 대한 처리를 표현할 수 있다. DAViS는, 새로운 형식의 오디오/비디오 데이타를 처리하는 부분을 손쉽게 통합하고, 하부 네트워크의 전송기술이나 컴퓨터시스템 관련 기술의 진보를 신속하고 자연스럽게 수용할 수 있도록 하는 유연한 구조를 가지고 있다. Abstract This paper describes the design and implementation of software framework which supports the processing of real-time stream data like audio and video in distributed object-oriented computing environment. DAViS(Distributed Object Framework supporting Audio/Video Streaming), proposed in this paper, abstracts software components concerning the processing of audio/video data as distributed objects and separates the transmission path of data between them from that of control information. Based on DAViS, distributed applications can be written in the same abstract level as is provided by the existing distributed environment in handling audio/video data. DAViS has a flexible internal structure enough to easily incorporate new types of audio/video data and to rapidly accommodate the progress of underlying network and computer system technology with very little modifications.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.179-188
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• 2018

Recently, blockchain technology has been recognized as one of the most important issues for the 4th Industrial Revolution which can be represented by Artificial Intelligence and Internet of Things. Cryptocurrency, named Bitcoin, was the first successful implementation of blockchain, and it triggered the emergence of various cryptocurrencies. In addition, blockchain technology has been applied to various applications such as finance, healthcare, manufacturing, logistics as well as public services. Distributed consensus algorithm is an essential component in blockchain, and it enables all nodes belonging to blockchain network to make an agreement, which means all nodes have the same information. For example, Bitcoin uses a consensus algorithm called Proof-of-Work (PoW) that gives possession of block generation based on the computational volume committed by nodes. However, energy consumption for block generation in PoW has drastically increased due to the growth of computational performance to prove the possession of block. Although many other distributed consensus algorithms including Proof-of-Stake are suggested, they have their own advantages and limitations, and new research works should be proposed to overcome these limitations. For doing this, above all things, we need to establish an evaluation method existing distributed consensus algorithms. Based on this motivation, in this work, we suggest and analyze assessment items by classifying them as efficiency and safety perspectives for investigating existing distributed consensus algorithms. Furthermore, we suggest new assessment criteria and their implementation methods, which can be used for a baseline for improving performance of existing distributed consensus algorithms and designing new consensus algorithm in future.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.9
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• pp.898-904
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• 2010

Unmanned autonomous forklifts have a great potential to enhance the productivity of material handling in various applications because these forklifts can pick up and deliver loads without an operator and any fixed guide. There are, however, many technical difficulties in developing such forklifts including localization, map building, sensor fusion, control and so on. Implementation, which is often neglected, is one of practical issues in developing such an autonomous device. This is because the system requires numerous sensors, actuators, and controllers that need to be connected with each other, and the number of connections grows very rapidly as the number of devices grows. Another requirement on the integration is that the system should allow changes in the system design so that modification and addition of system components can be accommodated without too much effort. This paper presents a network-based distributed approach where system components are connected to a shared CAN network, and control functions are divided into small tasks that are distributed over a number of microcontrollers with a limited computing capacity. This approach is successfully applied to develop an unmanned forklift.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.611-614
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• 2007

The IEEE 802.11 Task Group E has worked to enhance the legacy 802.11 MAC to expand support for applications with QoS requirements. EDCF(Enhanced Distributed Coordination Function) of IEEE 802.11e is enhanced from DCF(Distributed Coordination Function) of 802.11 and It has differential AC(Access Category). In this paper, we change parameters(AIFS, CWmax) and make an analysis of network performance. We use NS-2 to verify change of network performance.