• Journal of Korean Society of Water and Wastewater
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• v.33 no.5
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• pp.329-339
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• 2019

Recently, the advancement of information and communication technology(ICT) is expanding the connectivity through Internet of Things(IoT), and the media of connection is also expanding from wire/cable transmission to broadband wireless communication, which has significantly improved mobility. This hyperconnectivity has become a key element of the fourth industrial revolution, whereas the supervisory control network of purification plants in korea is operated as a communication network separated from the outside, thereby lagging in terms of connectivity. This is considered the best way to ensure security, and thus there is hardly any consideration of establishing alternatives to operate an efficient and stable communication network. Moreover, security for management of a commercialized communication network and network management solution may be accompanied by immense costs, making it more difficult to make new attempts. Therefore, to improve the conditions for the current supervisory control network of purification plants, this study developed a industrial security L2 switch that supports modbus TCP(Transmission Control Protocol) communication and encryption function of the transmission section. As a result, the communication security performance improved significantly, and the cost for implementing the network management system using Historical Trend and information of HMI(Human Machine Interface) could be reduced by approximately KRW 200 million. The results of this study may be applied to systems for gas, electricity and social safety nets that are infrastructure communication networks that are similar to purification plants.

• The Transactions of the Korea Information Processing Society
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• v.6 no.1
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• pp.11-20
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• 1999

Because conventional spatial databases process the spatial information that is valid at current time, it is difficult to manage historical information efficiently which has been changed from the past to current. Recently, there are rapid increasing of interest to solve this problem so that makes databases to support historical information as well as spatial management at the same time. It can be eventually used in a various application areas. The formal semantics in a database is used to represent database structures and operations in order to prove the correctiveness of them in terms or mathematics. It also plays an important role in database to design a database and database management system. So in this paper, we suggest spatiotemporal domain, object, data, and spatiotemporal geometric/topological operations. And we not only formalize relational algebra/calculus using formal semantics for a spatiotemporal data model, but also show the example of real orld with them.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.221-229
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• 2015

This paper looks into the measurement of modeling ability in different fields like science, mathematics, operations research and management science and emulates the ideas to system analysis and design where modeling is a very useful skill. An assessment tool was designed to measure the graphical modeling ability in systems analysis and design. It was administered to 92 students and submitted to 10 MIS experts and tested statistically for its reliability and validity.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.391-398
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• 2017

In this paper, we compared the performance of "Network Intrusion Detection System based on attack feature selection using fuzzy control language"[1] and "Intelligent Intrusion Detection System Model for attack classification using RNN"[2]. In this paper, we compare the intrusion detection performance of two techniques using KDD CUP 99 dataset. The KDD 99 dataset contains data sets for training and test data sets that can detect existing intrusions through training. There are also data that can test whether training data and the types of intrusions that are not present in the test data can be detected. We compared two papers showing good intrusion detection performance in training and test data. In the comparative paper, there is a lack of performance to detect intrusions that exist but have no existing intrusion detection capability. Among the attack types, DoS, Probe, and R2L have high detection rate using fuzzy and U2L has a high detection rate using RNN.

• Journal of the Korea Society for Simulation
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• v.31 no.2
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• pp.11-20
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• 2022

There is a critical need for AI assistance in guard operations of Army base perimeters, which is exacerbated by changes in the national defense and security environment such as force reduction. In addition, the possibility for human error inherent to perimeter guard operations attests to the need for an innovative revamp of current systems. The purpose of this study is to propose a real-time object detection AI tailored to military CCTV surveillance with three unique characteristics. First, training data suitable for situations in which relatively small objects must be recognized is used due to the characteristics of military CCTV. Second, we utilize a data augmentation algorithm suited for military context applied in the data preparation step. Third, a noise reduction algorithm is applied to account for military-specific situations, such as camouflaged targets and unfavorable weather conditions. The proposed system has been field-tested in a real-world setting, and its performance has been verified.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.2
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• pp.331-339
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• 2017

This paper proposes a thread pool management technique of an websocket server that is applicable to embedded systems. WebSocket is a proposed technique for consisting a dynamic web, and is constructed using HTML5 and jQuery. Various studies have been progressing to construct a dynamic web by Apache, Oracle and etc. Previous web service systems require high-capacity, high-performance hardware specifications and are not suitable for embedded systems. The node.js which is consist of HTML5 and jQuery is a typical websocket server which is made by open sources, and is a java script based web application which is composed of a single thread. The node.js has a limitation on the performance for processing a high velocity data on the embedded system. We make up a multi-thread based websoket server which can solve the mentioned problem. The thread pool is managed by a bit register and suitable for embedded systems. To evaluate the performance of the proposed algorithm, we uses JMeter that is a network test tool.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.437-448
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• 2016

The study conducted Comparative Analysis on the difference of College Scholastic Ability Data divided by type of admission process through the mileage program. Analysis result in following sequence. Leadership and relationships : CSAT(CSAT) > TOSR(subject), CSAT(CSAT+TOSR) is lower than each types ; mainly TOSR(total), TOSR(subject), CSAT(CSAT). Global : CSAT(CSAT+TOSR) & CSAT(CSAT) is higher than mainly TOSR(total) & TOSR(subject). Career and job search : TOSR(total) & TOSR(subject) is higher than mainly CSAT(CSAT+TOSR). Sum of mileage score : CSAT(CSAT) is higher than TOSR(subject) & CSAT(CSAT). Given this as a result, If you look simply at the activities of joint participation of leadership and relationships, student of mainly TOSR(total) admission do well college life with existing research. But with analysis results of K-Leader mileage this research shows that students of mainly CSAT(CSAT) admission do well college life. * CSAT(College Scholastic Ability Test), TOSR(a transcript of school records)

• Journal of Digital Convergence
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• v.19 no.5
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• pp.175-186
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• 2021

The roles and functions of domestic public libraries are diversifying, but various problems have emerged due to internally biased book lending. In addition, due to the 4th Industrial Revolution, public libraries have introduced a book recommendation system focusing on popular books, but the variety of books that users can access is limited. Therefore, in this study, the public library unborrowed book recommendation system was implemented limiting its spatial scope to Duryu Library in Daegu City to enhance the satisfaction of public library users, by using the loan records data (213,093 cases), user information (35,561 people), etc. and utilizing methods like cluster analysis, topic modeling, content-based filtering recommendation algorithm, and conducted a survey on actual users' satisfaction to present the possibility and implications of the unborrowed book recommendation system. As a result of the analysis, the majority of users responded with high satisfaction, and was able to find the satisfaction was relatively high in the class classified by specific gender, age, occupation, and usual reading. Through the results of this study, it is expected that some problems such as biased book lending and reduced operational efficiency of public libraries can be improved, and limitations of the study was also presented.

• Journal of Communications and Networks
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• v.12 no.4
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• pp.289-307
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• 2010

The problem of model selection arises in a number of contexts, such as subset selection in linear regression, estimation of structures in graphical models, and signal denoising. This paper studies non-asymptotic model selection for the general case of arbitrary (random or deterministic) design matrices and arbitrary nonzero entries of the signal. In this regard, it generalizes the notion of incoherence in the existing literature on model selection and introduces two fundamental measures of coherence-termed as the worst-case coherence and the average coherence-among the columns of a design matrix. It utilizes these two measures of coherence to provide an in-depth analysis of a simple, model-order agnostic one-step thresholding (OST) algorithm for model selection and proves that OST is feasible for exact as well as partial model selection as long as the design matrix obeys an easily verifiable property, which is termed as the coherence property. One of the key insights offered by the ensuing analysis in this regard is that OST can successfully carry out model selection even when methods based on convex optimization such as the lasso fail due to the rank deficiency of the submatrices of the design matrix. In addition, the paper establishes that if the design matrix has reasonably small worst-case and average coherence then OST performs near-optimally when either (i) the energy of any nonzero entry of the signal is close to the average signal energy per nonzero entry or (ii) the signal-to-noise ratio in the measurement system is not too high. Finally, two other key contributions of the paper are that (i) it provides bounds on the average coherence of Gaussian matrices and Gabor frames, and (ii) it extends the results on model selection using OST to low-complexity, model-order agnostic recovery of sparse signals with arbitrary nonzero entries. In particular, this part of the analysis in the paper implies that an Alltop Gabor frame together with OST can successfully carry out model selection and recovery of sparse signals irrespective of the phases of the nonzero entries even if the number of nonzero entries scales almost linearly with the number of rows of the Alltop Gabor frame.

• Steel and Composite Structures
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• v.46 no.6
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• pp.839-856
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• 2023

This work presents a simple four-unknown refined integral plate theory for mechanical and thermal buckling behaviors of functionally graded (FG) plates resting on Visco-Pasternak foundations. The proposed refined high order shear deformation theory has a new displacement field which includes indeterminate integral variables and contains only four unknowns in which any shear correction factor not used, with even less than the conventional theory of first shear strain (FSDT). Governing equations are deduced from the principle of minimum total potential energy and a Navier type analytical solution is adopted for simply supported FG plates. The Visco-Pasternak foundations is considered by adding the impact of damping to the usual foundation model which characterized by the linear Winkler's modulus and Pasternak's foundation modulus. The accuracy of the present model is demonstrated by comparing the computed results with those available in the literature. Some numerical results are presented to show the impact of material index, elastic foundation type, and damping coefficient of the foundation, on the mechanical and thermal buckling behaviors of FG plates.