• Proceedings of the Korean Society of Computer Information Conference
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• 2011.06a
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• pp.49-50
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• 2011

In this paper we collect data concerning sleep environments in a bedroom and analyze the relationship between the collected condition data and sleep. In addition, this paper detects scene changes from the subjects in a sleeping state and presents the physical conditions, reactions during sleep, and physical sensations and stimuli. To detect scene changes in image sequences, we used color histogram for the difference between the preceding frame and the current frame. In addition, to extract the tossing and turning for different situations, the subjects were instructed to enter the level of fatigue, the level of drinking, and the level of stomach emptiness.

• International Journal of Computer Science & Network Security
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• v.22 no.5
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• pp.266-276
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• 2022

The study aimed to pinpoint the effects of an educational environment based on gamification on developing achievement motivation among first-grade intermediate students. Using an achievement motivation scale, the study adopted a quasi-experimental design with experimental and control groups. The sample consisted of 52 students selected randomly from the first-grade intermediate students. They were studying in public intermediate schools in Jeddah at the time of this study. They were divided into two groups. The control group (n=24 respondent), and the experimental group (n=28 respondent). The results showed statistically significant differences at the level α ≥ 0.05 between the mean scores of the experimental group and the control group in the posttest of the achievement motivation measurement in favor of the experimental group. The study recommended using gamification in designing computer curricula and courses across educational stages in Saudi Arabia. It also recommends training the computer and information technology teachers on using gamification in their teaching.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.403-405
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• 2007

This paper presents the over-modulation strategy and indirect vector control drive of NPC type PWM inverter. NPC inverter has three level phase voltage output.It can perform in high voltage through assembling switching components. It has less harmonics and surge voltage stress at motor terminals than the 2 level inverter in same switching frequency through 3 level voltage. The conventional railway vehicle has used the vector control to MI=0.907 and the slip-frequency control from MI=0.907 to six-step mode. The slip-frequency control has bad motive power and slow torque control response. But vector control has good motive power and can instant torque control. In this paper, output voltage is controlled linearly from linear region to six-step mode by using over-modulation strategy. And NPC inverter is used.

• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.215-220
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• 2022

Emotion recognition is one of the most important and challenging areas of computer vision. Nowadays, many studies on emotion recognition were conducted and the performance of models is also improving. but, more research is needed on emotion recognition and sentiment analysis of video viewers. In this paper, we propose an emotion analysis system the includes a sentiment analysis model and an interest prediction model. We analyzed the emotional patterns of people watching popular and unpopular videos and predicted the level of interest using the emotion analysis system. Experimental results showed that certain emotions were strongly related to the popularity of videos and the interest prediction model had high accuracy in predicting the level of interest.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.1
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• pp.59-67
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• 2007

This paper presents a low power dual-level low voltage differential signaling (DLVDS) technique using current source switching for LCD driver ICs in portable products. The transmitter makes dual level signal that has two different level signal 400mVpp and 250mVpp while keeping the advantages of LVDS. The decoding circuit recovers the primary signal from DLVDS. The low power DLVDS is implemented using a $0.25{\mu}m$ CMOS process under 2.5V supply. The proposed circuit shows 800Mbps/2-line data rate and 9mW, 11.5mW power consumptions in transmitter and receiver, respectively. The proposed DLVDS scheme reduce power consumption dramatically compare with conventional one.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.268-275
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• 2015

This paper proposes a method of switching to improve power loss for the single-phase three-level NPC inverter. The conventional switching methods, which are called as the bipolar and unipolar switching methods, are used for single phase inverters using three-level topology. However, these switching method have disadvantage in the power loss. Because all of the switch are operated. To reduce the power loss of the three-level NPC inverter, clamp switching method is introduced in this paper. This way, one of the lag is fixed that switching loss is reduced. This paper analyzes and compares power losses of unipolar method and clamp method. The validity of the power loss analysis is verified through the simulation and experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.6
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• pp.122-128
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• 2011

This paper proposes a new control scheme of lithium ion battery units based on single phase multi-level converter. In the DC/AC converter applications using battery storage system, it is necessary to control the balancing voltage of individual battery units for high efficiency utilization. Using the proposed control scheme, the DC/AC single phase converter system is applied. To verify the effectiveness of the proposed control scheme, computer simulation is accomplished. In the computer simulation, lithium-ion battery units and single phase multi-level converter system are modeled and carried out using Psim simulation program. It will be helpful for design and applications of energy storage system with lithium-ion battery.

• Journal of Korea Game Society
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• v.12 no.5
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• pp.23-34
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• 2012

Computer games should keep user's immersion for fun. Flow can be occured on the balance of user's game skill level and the difficulty level of the challenges by an immersion theory. Computer games can make automatic control of the challenge difficulty level but user's game skill makes difficult to know instantly its level on gameplay because the skill is decided by game goals, user tendency, or user experience. In this paper, we proposed a method of measurement of user's gameplay skill level that we can know the skill level instantly on gameplay. The proposed methods require to be implemented in the stages of the design and implementation of the computer game to be used. Computer games can keep continuously the balance of user's game skill level and the difficulty level of the challenges in order to occur flow immersion by using the proposed measurement method and automatic control methods of the difficulty of game challenges.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.152-162
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• 1996

Diffraction gratings were designed to generate multiple beams for the real-time optical interconnection in free-space using a liquid crsytal television. Multi-level phase gratings consisted of stepped phase value, 0 to 2$\pi$, and generate a 5$\times$5 spot array, and V-shaped spot patterns which have a maximum diffraction efficiency of 78.84%. Simulated annealing technique was used to determine phase states of each pixel having uniform intensity and high diffraction efficiency. Through the optical interconnection experiments, we compared the diffraction characteristics of beam paterns obtained by binary-level, four-level, and eight-level phase gratings.

• Journal of The Korean Association of Information Education
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• v.9 no.2
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• pp.339-348
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• 2005

The trend of the computer education is shifting from problem-solving in the real world and using functions for it to behavioristic perspectives which encourage people to acquire the functions simply according to the applying programs of well-known companies. Thus, this research studies the computer instructional model which emphasizes the basic computer education and connections to the real world at the same time. In the constructivistic perspectives, this model emphasizes the learners activities, their using of meta-cognitive strategies to reflect their level of the lesson and collaborative-reflective learning of problem-solving. The research applied in the real computer skill education and according to the result of the research, I could find the experimental group got high level of learning achievement and this benefits to the high level group rather than low and middle group.