• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1261-1266
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• 2017

A random and systematic jitter suppressed delay locked loop (DLL)-based clock generator with a delay-time voltage variance converter (DVVC) and an averaging circuit (AC) is presented. The DVVC senses the delay variance of each delay stage and generates a voltage. The AC averages the output voltages of two consecutive DVVCs to suppress the systematic and random delay variance of each delay stage in the VCDL. The DVVC and AC averages the delay time of successive delay stages and equalizes the delay time of all delay stages. In addition, a capacitor with a switch working effectively as a negative feedback function is introduced to reduce the variation of the loop filter output voltage. Measurement results of the DLL-based clock generator fabricated in a one-poly six-metal $0.18{\mu}m$ CMOS process shows 13.4-ps rms jitter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.2 no.2
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• pp.73-79
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• 2001

In this paper, the transmitted noise reduction performance of piezoelectric smart panels is experimentally studied. The proposed piezoelectric smart panels are comprised of plate structure on which piezoelectric sensor/actuators are bonded and sound absorbing material is provided. It is a combination of passive and active approaches utilizing a passive effect at high frequencies and an active effect at low frequencies. To prove the concept of piezoelectric smart panels, an acoustic measurement experiment is performed. An acoustic tunnel is designed and its acoustic characteristics are tested. Below 800Hz, the tunnel exhibits a plane wave guide characteristics. When an absorbing material is bonded on a single plate, a remarkable transmitted noise reduction in mid frequency range is observed except the first resonance frequency. By enabling the active control of single smart panel with negative feedback control. about 10dB noise reduction is achieved at the resonance frequencies. The double smart panel got 4dB at the first resonance frequency and has more potential to reduce the transmitted noise in a wide range frequency. Piezoelectric smart panels incorporating passive absorbing material and active piezoelectric devices is a promising technology for noise reduction in a wide range frequency.

• IE interfaces
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• v.17 no.3
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• pp.338-348
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• 2004

OECD countries including Korea positively adopt performance-based budget systems which convert an input-centered system to an output-centered system to solve two baffling problems: public expense retrenchment and efficiency recovery of government management. Output management of IT project propelled in public sector becomes a prominent figure influenced by these keynote of policy. However, it is placed in difficult circumstances to develop a performance index and the methodology to cover characteristics of IT project, measuring the goal achievement of business and the customer contentment according to the phases of business progress. Existing studies of IT project accomplishment measurement have been fulfilled on the subject of business targeting on IT technology application, administrative information network business and national base of information network construction. Most of the studies have been executed using BSC or AHP to reflect synthetically business specifics of IT project from a methodological point of view. In this study, we propose a structural equation model (SEM) to develop a performance index which measures the outcome of IT project according to the phases of business progress, avoiding a simple presentation of project outcome or conceptual frame. The proposed SEM is applied to the survey results of "IT support project for Small and medium business". Based on the fitted model, we apply ACSI concept to develop an Information Technologization Success Index (ITSI). This index allows us comparison of several IT vendors as well as feedback information for further improvement.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.2
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• pp.179-186
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• 2015

In the indoor location estimation system, which has recently been actively studied, the received signal strength indicator contains a high level of noise when measuring the signal strength in the range between two nodes consisting of a receiver and a transceiver. To minimize the noise level, this paper proposes an improved adaptive smoothing filter that provides different exponential weights to the current value and previous averaged one of the data that were obtained from the nodes, because the characteristic signal attenuation of the received signal strength indicator generally has a log distribution. The proposed method can effectively decrease the noise level by using a feedback filter that can provide different weights according to the noise level of the obtained data and thus increase the accuracy in the distance and location without an additional filter such as the link quality indicator, which can verify the communication quality state to decrease the range errors in the indoor location recognition using ZigBee based on IEEE 802.15.4. For verifying the performance of the proposed improved adaptive smoothing filter, actual experiments are conducted in three indoor locations of different spatial sections. From the experimental results, it is verified that the proposed technique is superior to other techniques in range measurement.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.482-493
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• 2014

Many kinds of carbon emission monitoring systems or integrated systems have been developed so far. However, despite of the development of related techniques, they tend to be lack of statistic processing functions for feedback and policy-making data for users. In this study, a new CEMS (Carbon Emission Monitoring System) has been suggested and implemented in Sejong City, Korea. This system adapted automatic remote reading system from the site management agency as data hub to collect the electricity, gas and water usage of each household. The CEMS is consisted of 6 parts; carbon emission measurement, carbon emission standard setup and management, statistic analysis and the incentives. CEMS is distinguished with other systems for its UIs for users and the administrators. Also, data sharing with urban information system(UIS) of local government to produce information for users and policy-makers. This system makes it possible to investigate the change of energy consumption patterns, especially depending on the family structure and the housing characteristics. Furthermore, analyzing their correlation with carbon emission, it is expected to provide basic data used to establish urban environmental policies.

• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.66-73
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• 2007

Internet is a part of our common life and tremendous information is cumulated. In these trends, the personalization becomes a very important technology which could find exact information to present users. Previous personalized services use content based filtering which is able to recommend by analyzing the content and collaborative filtering which is able to recommend contents according to preference of users group. But, collaborative filtering needs the evaluation of some amount of data. Also, It cannot reflect all data of users because it recommends items based on data of some users who have similar inclination. Therefore, we need a new recommendation method which can recommend prefer items without preference data of users. In this paper, we proposed the apparel coordination system using personalized preference on the semantic web. This paper provides the results which this system can reduce the searching time and advance the customer satisfaction measurement according to user's feedback to system.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.1
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• pp.181-195
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• 1999

This study was done to develope a computer program for the evaluation of quality of nurisng care. Because the professional nursing care should be evaluated consistantly, computer program for the measurement of quality of nursing care is necessary for the effective and efficient management of nursing quality. In this study, a computer program for gastrointestinal surgery patients was developed as a module. Visual basic 4.0 was used as a basic program for the development of this program, and Access 7.0 was used for the data base construction of the program. The systems of evaluation criteria were hierarchical. and the titles of the hierarchical criteria were evaluation area-evaluation item-indicator. Each evaluation area contained several items and each evaluation item contained several indicators. The numbers of the evaluation criteria for gastrointestinal surgery patients were 7 evaluation areas, 32 evaluation items. and 71 indicators. Content validity of the evaluation criteria(in this case, 32 evaluation items) was .95. Scoring could be possible with the evaluation items. For the scoring types of this program were two. norm-referenced type(option 1) and criterion-referenced type(option 2), the user can choose the type according to the purpose of the evaluation. With this computer program. accurate and consistant evaluation of the quality of nursing care could be expected. Also. by the rapid feedback to nursing care practice. quality of nursing practice could be improved rapidly. and the systems of the evaluation criteria developed in this study could be used for the development of other moduls for various kinds of patient groups. Because this computer program was developed only for the purpose of research, it is necessary to be refined commercially to be used in real nursing situation.

• Journal of the Korean Society for Nondestructive Testing
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• v.19 no.5
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• pp.369-377
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• 1999

Recently, it is gradually raised necessity that thickness of thin film is measured accuracy and managed in industrial circles and medical world. Ultrasonic signal processing method is likely to become a very powerful method for NDE method of detection of microdefects and thickness measurement of thin film below the limit of ultrasonic distance resolution in the opaque materials, provides useful information that cannot be obtained by a conventional measuring system. In the present research. considering a thin film below the limit of ultrasonic distance resolution sandwiched between three substances as acoustical analysis model, demonstrated the usefulness of ultrasonic signal processing technique using information of ultrasonic frequency for NDE of measurements of thin film thickness. Accordingly, for the detection of delamination between the junction condition of boundary microdefect of thin film sandwiched between three substances the results from digital image processing.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.382-387
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• 1992

In order to obtain desired arc welding performance, we already developed an arc welding robot system that enabled coordinated motions of dual arm robots. In this system one robot arm holds a welding target as a positioning device, and the other robot moves the welding torch. Concerning to such a dual arm robot system, the positioning accuracy of robots is one important problem, since nowadays conventional industrial robots unfortunately don't have enough absolute accuracy in position. In order to cope with this problem, our robot system employed teaching playback method, where absolute error are compensated by the operator's visual feedback. Due to this system, an ideal arc welding considering the posture of the welding target and the directions of the gravity has become possible. Another problem still remains, while we developed an original teaching method of the dual arm robots with coordinated motions. The problem is that manual teaching tasks are still tedious since they need fine movements with intensive attentions. Therefore, we developed a 3-dimensional vision guided robot control method for our welding robot system with coordinated motions. In this paper we show our 3-dimensional vision sensor to guide our arc welding robot system with coordinated motions. A sensing device is compactly designed and is mounted on the tip of the arc welding robot. The sensor detects the 3-dimensional shape of groove on the target work which needs to be weld. And the welding robot is controlled to trace the grooves with accuracy. The principle of the 3-dimensional measurement is depend on the slit-ray projection method. In order to realize a slit-ray projection method, two laser slit-ray projectors and one CCD TV camera are compactly mounted. Tactful image processing enabled 3-dimensional data processing without suffering from disturbance lights. The 3-dimensional information of the target groove is combined with the rough teaching data they are given by the operator in advance. Therefore, the teaching tasks are simplified

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.9
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• pp.73-80
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• 2011

Conventional content-delivering services over the Internet were mainly based on the "best effort" scheme, which have been failed to provide a concrete profit model to the content providers. Mean while, a quality assuring network service is expected to provide reasonable profit model. However the relation between the cost and profit of the quality service is under studies. Recently, the Quality of Experience (QoE) was introduced to measure the real satisfaction level of users and used to develope profit models of quality services. The QoE can be used as a key tool for efficient service providing and also criteria for accurate satisfaction measurement. Especially, the QoE based feedback on the intention to pay for the service will be an important information to the content providers. This paper will introduce a model for the costs of quality services, and a profit model based on the QoE. The result of the paper can be used to develope business models for contents services over the growing networks.