• Journal of Power System Engineering
• /
• v.20 no.3
• /
• pp.22-28
• /
• 2016

Energy consumption rapidly increases with industrial development. therefore an interest in the efficiency of various power converters is increasing. Especially, the field of high-efficiency small motors widely distributed for industrial and family use is considered a very important field in terms of efficient energy usage, and accordingly, in the field of small electric equipment, the use of BLDC that allows high-efficiency drive in an inductor gradually increases. However, for the BLDC drive, information on the position of the rotor is essential. Both methods using a magnetic encoder and an optical encoder to detect the information on the position of the rotor obtain the information by three position sensitive devices, and if any one of these position sensitive devices fails to function, no positional information can be obtained, so there is a limitation in implementing a position sensor with high reliability. In the paper, proposes a new type of encoder that can obtain the positional information on the position of the rotor using a single position sensor in order to overcome the issues that it has to use numerous signal flows and that the reliability is reduced for the acquisition of positional information generated by using multiple position detectors. The encoder in the proposed method replaced the function of generating positional information from multiple sensors with the shape of the encoder plate and the capture function of MICOM. In order to verify the validity of the position detection technique by the proposed encoder, a prototype was produced, and an experiment using the capture function of DSP was conducted through this.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.5
• /
• pp.459-467
• /
• 2011

Rehabilitation exercises must maintain a patient's interest and permit a quantitative evaluation of the rehabilitation. We have developed a haptic-device system. When users move a grip, the haptic device provides a virtual force that either assists the movement of their arm or working against it. To investigate the functional effect of this system in a rehabilitation program, we used for five subjects with motor-function disorders and measured the grip position, velocity, force exerted on the grip, and EMG activities during a reaching task of one subject. The accuracy of the grip position, velocity and trajectories patterns were similar for all the subjects. The results suggested that the EMG activities were improved by applying the virtual force to the grip. These results can be used for the development of rehabilitation programs and evaluation methods.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.10
• /
• pp.673-679
• /
• 2016

Because of the growing interest in supercritical carbon dioxide power cycle technology owing to its potential enhancement in compactness and efficiency, supercritical carbon dioxide cycles have been studied in the fields of nuclear power, concentrated solar power (CSP), and fossil fuel power generation. This study introduces the current status of the research project on the supercritical carbon dioxide power cycle by Korea Institute of Energy Research (KIER). During the first phase of the project, the un-recuperated supercritical Brayton cycle test loop was built and tested. In phase two, researchers are designing and building a supercritical carbon dioxide dual Brayton cycle, which utilizes two turbines and two recuperators. Under the simulation condition considered in this study, it was confirmed that the design parameter has an optimal value for maximizing the net power in the supercritical carbon dioxide dual cycle.

• Journal of Information Technology Application
• /
• v.3 no.1
• /
• pp.1-21
• /
• 2001

The explosive growth of the Internet and the increasing popularity of the World Wide Web have generated significant interest in the development of electronic commerce in a global online marketplace. The rapid adoption of the Internet as a commercial medium is rapidly expanding the necessity of Web advertisement as a new communication channel. if proper Web advertisement could be suggested to the right user, then effectiveness of Web advertisement will be raised and it will help company to earn more profit. So, this article describes a personalized advertisement technique as a part of intelligent customer services for an electronic newspaper provide. Based on customers history of navigation on the electronic newspapers pages, which are divided into several sections such as politics, economics, sports, culture, and so on, appropriate advertisements (especially, banner ads) are chosen and displayed with the aid of machine learning techniques, when customers visit to the site. To verify feasibility of the technique, an application will be made to one of the most popular e-newspaper publishing company in Korea.

• Journal of the Korean Society for Library and Information Science
• /
• v.27
• /
• pp.265-289
• /
• 1994

Databases publicly available for online searching permit both citation and subject searching, however, subject searching has dominated the online search environment. Despite the power of citation searching, it may be underutilized This study explored the relationship between the number of cited references used in a citation search and information retrieval effectiveness, a relatively unstudied phenomenon. Three articles in the library and information science literature were chosen to represent sample questions. Cited reference searches were conducted for each article and each of its references. All searches were conducted in Social Scisearch and Scisearch on DIALOG. Relevance judgments on the retrieved citations were obtained from the authors of the original articles. This research focused on analyzing, in terms of information retrieval effectiveness, the overlap among postings sets retrieved by various combinations of cited references. The findings from the three case studies clearly showed that the more cited references used for the citation search, the better the performance, in terms of retrieving more relevant documents, up to a point of diminishing retums. In addition, generally the overall level of overlap among relevant documents sets was found to be low. Therefore, if only some of the cited references among many candidates are used for a citation search, a significant proportion of relevant documents may be missed. The analysis of the characteristics of cited references provided the ways to predict which cited refereces would be useful to improve information retrieval. The findings of this comprehensive exploratory study are of interest for both theoretical and practical reasons. They contribute to the development of a theoretical model for the effective use of the citation search. This model might also be implemented in operational online systems. In addition, the findings potentially will help online searchers improve their search strategies using the citation search so that they can better achieve their information retrieval goals: the retrieval of items relevant to a given question and the suppression of nonrelevant items.

• The Korean Journal of Food And Nutrition
• /
• v.22 no.1
• /
• pp.29-40
• /
• 2009

This study investigates the preferences Chinese have of Korean Kimchi and improvements for Chinese market adaptation of Kimchi through a survey. The questionnaire was conducted on 298 Chinese(108 males, 190 females) residing in Weihai, Yantai and Qingdao in Shandong province. The questionnaire form was developed and used for self-administration. The collected data were analyzed by SAS package. Among the subjects, 88.9% had experienced eating Kimchi and 58.8% liked Kimchi. The preference of Kimchi was significantly higher among males, workers, persons who had visited Korea, and persons interested in Korea compared to females, university students, persons who hadn't visited Korea, and persons with no interest in Korea. The reasons for liking Kimchi, in order of popularity, were for its 'refreshing taste'(64.9%), 'spicy taste'(57.7%), 'chewy texture'(47.2%), and 'sour taste'(35.1%). The reasons for disliking Kimchi were for its 'smell'(19.6%), 'sour taste'(16.2%), 'salty taste'(14.3%), and 'appearance'(8.7%). Of those surveyed, 97.6% had a positive opinion of Kimchi intake in the future. The intention of future consumption of Kimchi was significantly higher in females than males. The type of Kimchi wanted by Chinese was 'less seasoning'(53.4%), 'less spicy'(46.0%), 'sweeter taste'(39.3%), 'less salty'(37.2%), and 'no fish-like smell'(35.6%). Improvements for increasing Chinese Kimchi consumption were 'development of Kimchi according to Chinese preference'(81.2%), 'improvement of sanitation'(73.5%), 'decrease in the sale price of Kimchi'(72.8%), and 'convenient place for the purchase of Kimchi'(63.8%).

• 한국터널공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.233-247
• /
• 2005

Most tunnel lining material which has been used in the domestic is a concrete. But many problems as the construction period, the cost, and the crack occurrence for the design, construction, and management were happened in the concrete lining. For this reason, many research institutes like the Korea Highway Corporation recognize the necessity of an alternate material development and grow on the interest for that. So in this study, the seismic behaviour characteristics for the application of the Corrugated Steel Plate Lining in cut-and-cover tunnel are evaluated as several conditions for the backfill height, the cutting slope, and the relative density of backfill soil are changed. The compressive stress which is calculated in the Corrugated Steel Plate Lining by the seismic load is decreased as the backfill height increases and the cut slope grows gentle. Also, the moment shows the tendency of decrease according to the increase of the backfill height. But in the case of the relative density of the backfill soil is small, the moment increases according to the increase of the backfill height and affects the dynamic behaviour characteristic. So it is considered that the relative density of the backfill soil is also the important point. As the result in analyzing the seismic response characteristics of the reinforcement spacing of the Corrugated Steel Plate, the variation in the compressive force is hardly happened, but the moment and the shear force increase on the reinforcement spacing being narrow.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.12 no.4
• /
• pp.247-258
• /
• 2017

Since 2016 when the regulations related to vehicle structure and device modification were drastically revised, the car tuning market has been growing rapidly. Particularly, many drivers are showing interest in changing the interior and exterior according to their preference, or improving the specifications of their cars by changing the engine and powertrain, among others. Also, as the initial engine settings such as horse power and torque of the vehicle are made for stable driving of the vehicle, it is possible to change the engine performance, via Engine Control Unit (ECU) mapping, to the driver's preference. However, traditionally, ECU mapping could be only performed by professional car engineers and the settings were also decided by them. Therefore, this study proposed a system that collects data related to the driver's driving habits for a certain period and sends them to a cloud server in order to analyze them and recommend ECU mapping values. The traditional mapping method only aimed to improve the car's performance and, therefore, if the changes were not compatible with the driver's driving habits, could cause problems such as incomplete combustion or low fuel efficiency. However, the proposed system allows drivers to set legally permitted ECU mapping based on analysis of their driving habits, and, therefore, different drivers can set it differently according to the vehicle specifications and driving habits. As a result, the system can optimize the car performance by improving output, fuel efficiency, etc. within the range that is legally permitted.

• Journal of IKEEE
• /
• v.15 no.3
• /
• pp.227-234
• /
• 2011

The Interest in robotics has been steadily increasing in recent times both in Korea as well as abroad. Research on robots for new and diverse fields is ongoing. This study discusses the current research and development on robot actuator, which are used to control the joints of robots, and focuses on developing more efficient technology for joint control, as compared with the current technologies. It also aims to find means to apply the abovementioned technology to diverse industrial fields. We found that easy and effective control of actuators could be achieved by using ZigBee sensor networks, which were widely being used on wireless communications. Throughout the experiments it is proved that the developed wireless actuator could be used for easy control of various robot joints. This technology can be effectively applied to develop two-legged robots that will be able to walk like human, or even quadruped and hexapod robots. It can also be applied to motors used in industry. In this study, we develop an extremely minimized ZigBee sensor network module that can be used to control various servo motors with low power consumption even if it is long distances. We realized effective wireless control by optimizing the ZigBee antenna, and were able to quickly check the status of relevant Tree node through mutual communication between the servo motors composing the ZigBee sensor network and the main server control modules. The developed Servo Motor with ZigBee sensor network modules can be applied in both robotics as well as for home or factory automation.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.2
• /
• pp.149-156
• /
• 2018

Now RC cars have become a culture where everyone who wants to feel precise control and rushing instinct regardless of sex, young or old can participate. In addition, RC cars have attracted a lot of people because they can feel the feeling of driving while driving a car in a small, lightweight body. In line with these trends, various development companies are focusing on functional aspects such as driving and speed improvement for each environment and their sophistication. Of course, driving performance alone can bring a tremendous ripple effect, but what you can do with a RC car is only part replacement and motor modification. Therefore, we will develop RC car based on raspberry pie, control by application, add various functions through sensor recognition, and develop RC car that can travel through video information that can be obtained using web cam. As a small RC car, we carry out research that can combine the functions that can be used as a robot that moves at various construction sites and accident sites where people can not enter, and which can attract users' interest.