• Journal of Sensor Science and Technology
• /
• v.17 no.6
• /
• pp.406-413
• /
• 2008

We have been implemented simple statistical pattern recognition methods for harmful gases classification using gas sensors array fabricated by MEMS (Micro Electro Mechanical System) technology. The performance of pattern recognition method as a gas classifier is highly dependent on the choice of pre-processing techniques for sensor and sensors array signals and optimal classification algorithms among the various classification techniques. We carried out pre-processing for each sensor's signal as well as sensors array signals to extract features for each gas. We adapted simple statistical pattern recognition algorithms, which were PCA (Principal Component Analysis) for visualization of patterns clustering and MLR (Multi-Linear Regression) for real-time system implementation, to classify harmful gases. Experimental results of adapted pattern recognition methods with pre-processing techniques have been shown good clustering performance and expected easy implementation for real-time sensing system.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.10 no.1
• /
• pp.45-53
• /
• 1998

Video monitoring techniques and their applications to beaches were reviewed. The recent development of video hardware and image process made it possible to measure shoreline changes, sandbar morphology, wave runup, swash motion, and so on using video camaras. Especially, quantitative information from the video image can be obtained by digitization of image, rectification procedure, and image process. Using video monitoring techniques, measurements can be made at much lower cost and for long periods of time compared to the traditional measurement techniques, although these techniques are of lower accuracy and provide only indirect information on the land and water surface.

• Korean Institute of Interior Design Journal
• /
• v.15 no.3 s.56
• /
• pp.75-82
• /
• 2006

Discussions on transparency have been being analyzed as variedly as the diversity itself in contemporary architecture. Though it is inappropriate to summarize the discussions into several specific viewpoints, as the notional classifications on transparency are varied according to the points of individual researchers, it can be said that, by approaching with the standpoint of the designers who may have various difficulties in the course of design, the meaning of this thesis lies largely in the fact that it attempted to study the architectural application techniques of transparency notion both through surface aspect which could be said to decide on the appearance of the architecture shape and through, in physical aspects as a combination of space components comprising the inner space, spatial aspect to which architectural techniques of transparency notion are applied. Through these, we conclude as follows. 1. Representation Techniques of Transparency in Surface : Transparency from surface viewpoint could be categorized into 1) emphasis on property-of-matter, 2) lightness of Literal material itself, 3) visual ambivalence, and 4) dematerialized hyper-surface. 2. Representation Techniques of Transparency in Space : In spatial viewpoint, transparency is summarized into sub-viewpoints as 1) straightforward space 2) ambiguous spacer 3) expanded space

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2004.05b
• /
• pp.190-195
• /
• 2004

In this paper, Error rate performance of Convolution coded DS-CDMA 16 QAM signal is analyzed using selective combining diversity reception techniques and maximal ratio combining diversity reception techniques under the environments of Rician fading. With the results of analysis, maximal ratio combining diversity reception techniques provides the performance improvement of about 3-8[㏈] over selective combining diversity reception techniques for the good error performance lot data communication. And it is found that a synergistic performance improvement is show to both diversity reception and Convolution coding, techniques overcoming mobile wireless data communication channel environment.

• Journal of KIISE:Databases
• /
• v.28 no.4
• /
• pp.723-731
• /
• 2001

As XML has become and emerging standard for information exchange on the World Wide Web it has gained attention in database communities of extract information from XML seen as a database model. Data in XML can be mapped to semistructured dta model based on edge-labeled graph and queries can be processed against it Here we propose new query optimization techniques using DTDs(Document Type Definitions) which have the schema information about XML data. Our techniques reduce traditional index techniques Also, as they preserve source database structure, they can process many kinds of complex queries. we implemented our techniques and provided preliminary performance results.

• Membrane and Water Treatment
• /
• v.6 no.4
• /
• pp.339-349
• /
• 2015

Experiments were carried out using granular activated carbon (GAC) adsorption techniques to treat wastewater contaminated with organic compounds caused by diverse human activities. Two techniques were assessed: adsorbent GAC prepared from coconut shell (GACC) and adsorbent GAC from palm shell (GACP). A comparison of these two techniques was undertaken to identify ways to improve the efficiency of the treatment process. Analysis of the processed wastewater showed that with GACC the removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, total suspended solids (TSS) and total dissolved solids (TDS) was 65, 60, 82, 82 and 8.7%, respectively, while in the case of GACP, the removal efficiency was 55, 60, 81, 91 and 22%, respectively. It can therefore be concluded that GACC is more effective than GACP for BOD removal, while GACP is better than GACC for TSS and TDS removal. It was also found that for COD and turbidity almost the same results were achieved by the two techniques. In addition, it was observed that both GACC and GACP reduced pH value to 7.9 after 24 hrs. Moreover, the optimal time period for removal of BOD and TDS was 1 hr and 3 hrs, respectively, for both techniques.

• Journal of the Korea Society of Computer and Information
• /
• v.6 no.3
• /
• pp.50-55
• /
• 2001

We review error resilience techniques for real-time video transport over unreliable networks. For error control on the source coding level, each decoder has to make provisions for error detection, resynchronization. and error concealment. and we review techniques suitable for that purpose. Further, techniques are discussed for intelligent processing of acknowledgment information by the coding control to adapt the source coder to the channel. We review and compare error tracking, error confinement. and reference picture selection techniques for channel-adaptive source coding. We review how feedback-based source codings are related with the precompressed video stored on a media server

• Journal of Engineering Education Research
• /
• v.24 no.3
• /
• pp.58-69
• /
• 2021

It is very necessary to have a creative problem-solving capacities to learn various majors and liberal arts based on the major, and to solve the bottleneck techniques led by students. In this study, the existing creative problem-solving curriculums, 'Methodology of Inventive Problem Solving' based on TRIZ, were improved and applied, and industrial bottleneck techniques were provided to students to solve these techniques. To improve the curriculum, 1) improvement of instructional objectives and learning contents, 2) improvement of evaluation methods and contents (reflecting the evaluation of instructor and students), and 3) learning satisfaction survey were conducted in the following order. As a result of the application of the improved curriculum, the level of activities for each team was improved, and when the core process was well understood, the evaluation of team activities was also excellent, but there was a tendency to focus on methods that are relatively easy to apply in the problem solving process. In the final exam (learning contents evaluation), teams with difficult understanding of the TRIZ theory or low team activities showed a relatively high trend, but the difference in level between divisions was slightly reduced.

• The Journal of the Korea Contents Association
• /
• v.20 no.12
• /
• pp.49-57
• /
• 2020

This study predicts the ratio of added value, which represents the competitiveness of export industries in South Korea, using various machine learning techniques. To enhance the accuracy and stability of prediction, forecast combination technique was applied to predicted values of machine learning techniques. In particular, this study improved the efficiency of the prediction process by selecting key variables out of many variables using recursive feature elimination method and applying them to machine learning techniques. As a result, it was found that the predicted value by the forecast combination method was closer to the actual value than the predicted values of the machine learning techniques. In addition, the forecast combination method showed stable prediction results unlike volatile predicted values by machine learning techniques.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.5
• /
• pp.1871-1890
• /
• 2021

The transition toward a contactless society has been rapidly progressing owing to the recent COVID-19 pandemic. As a result, the IT environment of organizations and enterprises is changing rapidly; in particular, data security is expanding to the private sector. To adapt to these changes, organizations and companies have started to securely transfer confidential data to residential PCs and personally owned devices of employees working from home or from other locations. Therefore, organizations and companies are introducing streaming data services, such as the virtual desktop infrastructure (VDI) or cloud services, to securely connect internal and external networks. These methods have the advantage of providing data without the need to download to a third terminal; however, while the data are being streamed, attacks such as screen shooting or capturing are performed. Therefore, there is an increasing interest in prevention techniques against screen capture threats that may occur in a contactless environment. In this study, we analyze possible screen capture methods in a PC and a mobile phone environment and present techniques that can protect the screens against specific attack methods. The detection and defense for screen capture of PC applications on Windows OS and Mac OS could be solved with a single agent using our proposed techniques. Screen capture of mobile devices can be prevented by applying our proposed techniques on Android and iOS.