• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8B
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• pp.667-680
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• 2008

In this work, we present the results of our empirical study on 802.11 wireless LAN network traffic. We collect the packet trace from existing campus wireless LAN infra-structure. We analyzed four different data sets: aggregate traffic, upstream traffic, downstream traffic, tcp only packet trace from aggregate traffic. We analyze the time series aspect of underlying traffic (byte count process and packet count process), marginal distribution of time series, and packet size distribution. We found that in all four data sets there exist long-range dependent property in byte count and packet count process. Inter-arrival distribution is well fitted with Pareto distribution. Upstream traffic, i.e. from the user to Internet, exhibits significant difference in its packet size distribution from the rests. Average packet size of upstream traffic is 151.7 byte while average packet size of the rest of the data sets are all greater than 260 bytes. Packets with full data payloads constitutes 3% and 10% in upstream traffic and the downstream traffic, respectively. Despite the significant difference in packet size distribution, all four data sets have similar Hurst values. The Hurst alone does not properly explain the stochastic characteristics of the underlying traffic. We model the underlying traffic using fractional-ARIMA (FARIMA) and fractional Gaussian Noise (FGN). While the fractional Gaussian Noise based method is computationally more efficient, FARIMA exhibits superior performance in accurately modeling the underlying traffic.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.896-905
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• 2021

In the field of SIEM(Security information and event management), many studies try to use a feedback system to solve lack of completeness of training data and false positives of new attack events that occur in the actual operation. However, the current feedback system requires too much human inputs to improve the running model and even so, those feedback from inexperienced analysts can affect the model performance negatively. Therefore, we propose "active model improving feedback technology" to solve the shortage of security analyst manpower, increasing false positive rates and degrading model performance. First, we cluster similar predicted events during the operation, calculate feedback priorities for those clusters and select and provide representative events from those highly prioritized clusters using XAI (eXplainable AI)-based event visualization. Once these events are feedbacked, we exclude less analogous events and then propagate the feedback throughout the clusters. Finally, these events are incrementally trained by an existing model. To verify the effectiveness of our proposal, we compared three distinct scenarios using PKDD2007 and CSIC2012. As a result, our proposal confirmed a 30% higher performance in all indicators compared to that of the model with no feedback and the current feedback system.

• Archives of design research
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• v.12 no.2
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• pp.89-95
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• 1999

Carlo H. Sequin, a computer scientist, became to know a sculpture of subtle space construction which was created by Brent Collins, a sculptor, and introduced it as 'Visual Mathematics' in a journal. Sequin who was able to deduce a basic logic of the construction, has developed a software which can be used for virtual modeling merely by substituting simple numerical values using a computer and supplied it to Collins. The present author who was exposed to their collaboration works through series of their papers published in the journal, Leonardo, introduces the Collins' sculptures and the author's modeling procedures of animation works both of which show many common things in visual characteristics and modeling expansion method. The author investigates the mathematical characteristics which is used as a basic motive of modeling and then supplied as a principal visual characteristics of a material. 'Modeling Development by Principle Expansion,' in which the expansion is developed on the base of space twist as for Collins whereas the space section as for the present author, is introduced in this study. With the same stream of the mutual reaction in 'arts, sciences and technology' which has been stressed with the development of sciences and technology, this modeling technology is suggested as a research theme which has a possiblity of various applications.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.873-884
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• 2004

This research provides the solution of defect problem and detection of defect and its causes that happen on software development. For developing a reliable software, a key factor is to find and manage defects that are during software development. Based on defect items analysis, we understand associated relation between defects and design defect opportunity tree. Developing the similar project, we can estimate defect and prepare to solve defect by using defect management opportunity tree.

• Korean Journal of Construction Engineering and Management
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• v.16 no.2
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• pp.38-45
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• 2015

The risk analysis phase of construction risk management process is subdivided into the qualitative risk analysis that plays a major role, and the quantitative risk analysis acting as a supportive role. The traditional calculation method for quantifying a risk value that has been applied so far is an equation to multiply a probability by an impact simply, but its result shows the low risk value biased distribution. Although another equation that shows the high risk biased distribution as an alternative of traditional method was proposed, both of the low or high risk biased equations do not match with the statistical general knowledge that most natural phenomenons are close to the normal distribution. This study proposes a new risk value calculation method that is concentrated to the moderate risk value. Because the risk value distribution by a new method shows a normal shape similar to natural phenomenon, it helps to choose a middle level not biased to the low or high levels when choosing the level of risk response. Furthermore, it could contribute to improve the flexibility and rationality of risk analysis method by providing additional options for the risk value calculation.

• Journal of Korea Game Society
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• v.3 no.2
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• pp.35-41
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• 2003

There arose problems of double investment about the game engine part when a lot of game software similar to the property and procedure processed in the game engine develop new game without the reference or reuse in the other games. In particular, using various software development processes is one of main problems of double investment when the enterprises for the game software development develop games now Accordingly, because it does not make standardization of process about the game engine, it does not understand and reuse products created in process of the other software development process in development now. Accordingly, the newly analyzed and designed software was big problems with the present game software about the game engine process similar to the other game software when the enterprises for any game software develop a special game. For solving these problems, this study is to suggest the process improvement about the game engine development, analysis of structure and relation, classification and combination method by the class and module, implementation of storage, and processor model in order to apply the development method based on the component.

• Journal of Information Technology and Architecture
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• v.9 no.2
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• pp.167-176
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• 2012

In Korean military measuring systems interoperability is based on LISI (Level of Information System Interoperability) model at the requirement generation and acquisition process. However, LISI model cannot be used for interoperability measurement of system of systems (SoS) because LISI model is focused on interoperability measurement of a given system or system pair. Also, LISI model cannot provide quantitative information for interoperability decision because of qualitative rather than quantitative approach. This paper proposes a quantitative interoperability measurement methodology of SoS. At the proposed methodology, mission threads and supporting systems are identified using architecture approach, and Interoperability of SoS is measured with systems multiplicity and resemblance coefficient. Finally, a case study is presented to show the usefulness of the methodology.

• Korean Journal of Construction Engineering and Management
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• v.14 no.1
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• pp.133-143
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• 2013

BIM can be utilized variously in construction management(CM) in the respect that it helps to manage comprehensively the construction information and make reliable decisions, but the adoption of BIM is insufficient in the CM area. The purpose of this study is to develop work process models and their guides in order to utilize BIM effectively in CM work at construction stage. This study defined BIM functions as 'BIM converting design', 'Model review', 'Data extraction', 'Automatic estimate', '4D simulation', 'Drawing creation', 'Engineering sector linkage analysis' through literature search, and generated CM works applicable to BIM by analyzing the CM work and process. This study developed BIM-based CM work process models by reconstructing the existing work process in connection with BIM function through an analysis on the relationship between BIM function and CM work, and reconstructing the role of each project participants. In order to improve the usefulness of the developed models, guides that described the BIM works of project participants were prepared through interviews and case studies. To validate the utilization of the models, a comparative analysis on the BIM process of precedent studies was also made and a survey was conducted on experts. This study can contribute to increasing the utilization of BIM in the CM area and can be helpful for CM companies to develop an in-house BIM guide. In the future, it will be necessary to make an assessment on the models from a business perspective through case applications and constantly update BIM-based CM work process model in consideration of the expansion of CM work due to the application of BIM.

• The KIPS Transactions:PartD
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• v.9D no.5
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• pp.859-864
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• 2002

The life cycle of new information technologies is getting shorter, and the technologies are becoming more complex and difficult to understand. The need to better understand adoption of object orientation motivates this paper. Adoption of object orientation should certainly be influenced by prior software process technologies, such as the process-oriented structured methods, because object orientation is considered to be a paradigm shift from conventional software process technologies. This study aims to empirically analyze knowledge interference of the structured methods with object orientation. A two factorial quasi-experimental design is set forth. The period of experience using the structured methods and the period of experience using object orientation are selected as two independent variables, and the perceived ease of use is chosen as one dependent variable. Data are gathered from active members of Data Processing Management Association (DPMA), who have experiences in using both the structured methods and object orientation. The final results empirically show that previous experience using the structured methods negatively influences the perception of using object orientation that is one of critical factors to technology adoption. It is suggested here that a future study dealing with the same research topic in other countries will provide new insights about comparative studies.

• Korean Journal of Construction Engineering and Management
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• v.15 no.6
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• pp.26-34
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• 2014

Highway construction is a combination of linear, repetitive, and highly equipment intensive operations. Various types of construction equipment are deployed to ensure undisrupted performance of construction, and thus productivity improvement and cost-saving can be achieved through well-thought-out planning. The selection of construction equipment is dependent upon construction sequence, site conditions, and construction methods. In the process of planning, management should consider various types of construction methods per each type of construction operation. Also, management should map out proper construction equipment operation plan that takes the construction duration and cost measures into consideration. However, limited availability of historic data from the similar types of operations has been a stumbling block to proper construction planning, making the operations performed based upon experience and intuition guided by rules-of-thumb. As a consequence, the planing phase rarely provided an adequate validity in the implementation phase. The researchers developed a process logic for each construction type that management can utilize from early phase of highway construction planning process. Moreover, derived the construction equipment combination optimized for efficiency by using the process simulation technique. The developed method is expected to be useful for the decision-making process that aims to evaluate efficiency of various process plans and to ensure optimal selection of construction equipment for highway construction projects.