• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.870-872
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• 2007

Sensor networks have been widely applied for data collection. Due to the energy limitation of the sensor nodes and the most energy consuming data transmission, we should allocate as much work as possible to the sensors, such as data compression and aggregation, to reduce data transmission and save energy. Querying extreme values is a general query type in wireless sensor networks. In this paper, we propose a novel querying method called Two-Level Filter (TLF) for querying extreme values in wireless sensor networks. We first divide the whole sensor network into domains using the Distributed Data Aggregation Model (DDAM). The sensor nodes report their data to the cluster heads using push method. The advantages of two-level filter lie in two aspects. When querying extreme values, the number of pull operations has the lower boundary. And the query results are less affected by the topology changes of the wireless sensor network. Through this method, the sensors preprocess the data to share the burden of the base station and it combines push and pull to be more energy efficient.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.6-11
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• 2021

Routing protocols play a pivotal role in the energy management and lifespan of any Wireless Sensor Network. Lower network lifetime has been one of the biggest concerns in LEACH protocol due to dead nodes. The LEACH protocol suffers from uneven energy distribution problem due to random selection of a cluster head. The cluster head has much greater responsibility compared to other non- cluster head nodes and consumes greater energy for its roles. This results in early dead nodes due to energy lost for the role of cluster- head. This study proposes an approach to balance the energy consumption of the LEACH protocol by using a semi-deterministic opportunity coefficient to select the cluster head. This is calculated in each node with the battery energy level and node ID. Ultimately, based on the opportunity cost, cluster head will be selected and broadcasted for which other nodes with higher opportunity cost will agree. It minimizes the chances of nodes with lower battery level being elected as cluster head. Our simulation experiments demonstrate that cluster heads chosen using our proposed algorithm perform better than those using the legacy LEACH protocol.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1019-1022
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• 2002

The current paper proposes a wavelet-based digital watermarking algorithm using statistical characteristic of image and human visual system (HVS). The original image is decomposed into 4-level using a discrete wavelet transform (DWT), then the watermark is embedded into the perceptually significant coefficients (PSCs) of the image. In general, the baseband of a wavelet-decomposed image includes most of the energy of the original image, thereby having a crucial effect on the image quality. As such, to retain invisibility, the proposed algorithm does not utilize the baseband. Plus, the wavelet coefficients on the lowest level are also excluded in the watermark-embedding step, because these coefficients call be easily eliminated and modified by lossy compression and common signal processing. As such, the PSCs are selected from all subbands, except for the baseband and subbands on the lowest level. Finally, using the selected PSCs, the watermark is then embedded based on spatial masking of the wavelet coefficients so as to provide invisibility and robustness. Computer simulation results confirmed that the proposed watermarking algorithm was more invisible and robust than conventional algorithms.

• Management & Information Systems Review
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• v.2
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• pp.237-266
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• 1998

The purpose of this study was to analyze the differences of application level the computer programming languages in major. The method of this study is the empirical method based on theoretical one with the previous bibliographical suduies. The sample consists of 268 listed university disclosing over the period of Dec. 1. 1997 to Du. 15. 1997. The samples were 10 university in university of Seoul, Pusan, Masan City, Korea. The data were collected by questionnaire research through interview with each person. The analysis data was carried to 268 samples by using SPSS/PC for Windows Version 7.5 statistical package. Statistical methods such as frequency analysis, chi-square test, ANOVA test, correlation analysis were used to test the research questions. This paper focuses on the design of the hypothesis test show that the 2 type are significantly different in major of university students. Before the test of research questions performed it frequency analysis by using the factor score that bring each items. The research type of 2 guoups, that is, BA Group(business administration group) and NBA Group(non-business administration guoup). To summarize the result of this study is as follows ; (1) Hypothesis 1 : Concerning about computer programming language in major, the significant difference is application the present condition. (2) Hypothesis 2 : Concerning about computer programming language in major, the significant difference is application level. (3) Hypothesis 3 : Concerning about each application software in major, the significant difference is application level. According to the results of this study, it is found that (1) Hypothesis 1 related In application the present condition of computer programming language was accepted its all at 0.05 % significance level. (2) Hypothesis 2 related to application level of computer programming language was accepted its all at 0.05 % significance level. (3) Hypothesis 3 related to application level of each application software was rejected its all. at 0.05 % significance level.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.181-189
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• 2016

This study examined three elementary school computing curriculum - the CSTA K-12 computer science standards, the computing programme of the national curriculum in England, and the 2015 national curriculum in Korea - focusing on the educational objectives with the perspective of the revision of Bloom's Taxonomy of Educational Objectives. The CSTA K-12 computer science standards mainly addressed applying procedural knowledge and using digital technology is the main theme. The computing programme in England concentrated on understanding factual and conceptual knowledge of computer science, such as algorithms. The 2015 national curriculum also addressed applying procedural knowledge, but the main focus is making softwares and robots. The findings of this comparative analysis suggest that it is needed to set up concrete educational objectives for lower grade and make them related to the secondary education to make more coherent elementary-level learning objectives. And elementary-level computing learning objectives are needed to be organized with the perspective of knowledge and cognitive process level.

• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.207-212
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• 2008

There are several sensors in the liquid cargo ship. In the liquid cargo ship, we can get values from various sensors that are level sensor, temperature sensor, pressure sensor, oxygen sensor, VOCs sensor, high overfill sensor, etc. It is important to guarantee the reliability of sensors. In order to guarantee the reliability of sensors, we have to study the diagnosis of sensor fault. The technology of smart sensor is widely used. In this paper, the technology of smart sensor is applied to diagnosis of level sensor fault for liquid cargo ship. In order to diagnose sensor fault and find the sensor position, in this paper, we proposed algorithms of diagnosis of sensor fault using independent sensor diagnosis unit and self fault diagnosis using sensor modeling. Proposed methods are demonstrated by experiment and simulation. The results show that the proposed approach is useful. Proposed methods are useful to develop smart level sensor.

• Journal of the Korea Society of Computer and Information
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• v.18 no.12
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• pp.11-19
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• 2013

This paper proposes an algorithm using vibration signals and texture analysis for mechanical fault diagnosis of an induction motor. We analyze characteristics of contrast and pattern of an image converted from vibration signal and extract three texture features using gray-level co-occurrence model(GLCM). Then, the extracted features are used as inputs of a multi-level support vector machine(MLSVM) which utilizes the radial basis function(RBF) kernel function to classify each fault type. In addition, we evaluate the classification performance with varying the parameter from 0.3 to 1.0 for the RBF kernel function of MLSVM, and the proposed algorithm achieved 100% classification accuracy with the parameter of the RBF from 0.3 to 1.0. Moreover, the proposed algorithm achieved about 98% classification accuracy with 15dB and 20dB noise inserted vibration signals.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.75-84
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• 2019

This study was a cross-sectional descriptive research that investigate the level of addiction and analyzed the impact of computer game addiction from 20 to 30 years old on communication capabilities. The purpose of this study was to investigate the level of game addiction according to general characteristics and to confirm the effect of computer game addiction on communication ability. There were a total of 220 participants in the study. This survey for this study was a self-reporting questionnaire, research tools for this study were developed by Lee (2000) using game addiction and Communication ability developed by Frits et al., (1999). Data analysis was analyzed with frequency analysis, t-test, ANOVA, and Regression using SPSS 18.0. As a result of analysis, the difference between game addiction and communication ability by gender was appeared to be different under statistical significance levels: game addiction (t=-.9.2, p<0.01), subcomponents of communication ability, concentration (t=7.20, p<0.01), understanding (t=6.13, p<0.01), response (t=6.22, p<0.01), memory (t=2.88, p<0.05). The highest level of game addiction was appeared between 28 and 30 years old under statistical significance (p<0.01). Finally computer game addiction affects understanding, a subcomponent of communication capabilities.

• Journal of the Korea Society of Computer and Information
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• v.24 no.6
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• pp.37-43
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• 2019

This study focused on the design and development of contents using Unplugged CS method to learn computer science knowledge. With the strengthening of software education, all universities students including elementary and junior high school students are demanding knowledge of computer science centered on the computational thinking. We have developed educational contents using unplugged computing method as a way to effectively learn the concept of computer science. First, we analyze the related research of Unplugged CS theory and investigate the educational method accordingly. And we divided the areas of computer science and selected learning concepts in each area. The contents of learning were divided into basic and intermediate classes considering the level of the learner. The subject of learning contents was selected evenly in the area of computer science and it consisted of 16 basic subjects and 16 intermediate subjects based on concepts that are important in each field. In order to confirm the validity of the Unplugged CS learning topic and the development contents for computer science, we conducted expert reviews and content validity tests. As a result of the validity test, the validity of the learning topic and area selection was found to be more than .92 for the CVI value and the validity of the 32 subject learning contents was over .935 in basic level and .925 in intermediate level for the CVI values. Based on the design contents, we developed digital contents for online learning and put them in the system. We expect that this study will contribute to the understanding of computer science for all, including elementary and junior-high school students as well as students at software - oriented universities, and contribute to the spread of software education.

• Journal of Korea Multimedia Society
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• v.21 no.12
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• pp.1431-1438
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• 2018

In this paper, we proposed a river water level detection and tracking of the river or dams based on image processing system. In past, most of the water level detection system used various water sensors. Those water sensors works perfectly but have many drawbacks such as high cost and harsh weather. Water level monitoring system helps in forecasting early river disasters and maintenance of the water body area. However, the early river disaster warning system introduces many conflicting requirements. Surveillance camera based water level detection system depends on either the area of interest from the water body or on optical flow algorithm. This proposed system is focused on water scaling area of a river or dam to detect water level. After the detection of scale area from water body, the proposed algorithm will immediately focus on the digits available on that area. Using the numbers on the scale, water level of the river is predicted. This proposed system is successfully tested on different water bodies to detect the water level area and predicted the water level.