• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.6
• /
• pp.1114-1119
• /
• 2002

In this paper, the well-conditioned observer is designed to be insensitive to the ill-conditioning factors in transient and steady-state observer performance. A condition number based on 12-norm of the eigenvector matrix of the observer matrix has been proposed on a principal index in the observer performance. For the well-conditioned observer design, the non-normality measure and the observability condition of the observer matrix are utilized. The two constraints are specified into observer gain boundary region that guarantees a small condition number and a stable observer. The observer gain selected in this region guarantees a well-conditioned and observable property. In this study, this method is applied to the Luenberger observer and Kalman filters for small order systems. In designing Kalman filters, the ratio of the process noise covariance to the measurement noise covariance is a design parameter and its effect on the condition number is investigated.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2001.10a
• /
• pp.313-318
• /
• 2001

In this paper, the well-conditioned observer is designed to be insensitive to the ill-conditioning factors in transient and steady-state observer performance. A condition number based on $L_2-norm$ of the eigenvector matrix of the observer matrix has been proposed on a principal index in the observer performance. For the well-conditioned observer design, the non-normality measure and the observability condition of the observer matrix are utilized. The two constraints are specified into observer gain boundary region that guarantees a small condition number and a stable observer. The observer gain selected in this region guarantees a well-conditioned and observable property. In this study, this method is applied to the Luenberger observer and Kalman filters. In designing Kalman filters for small order systems, the ratio of the process noise covariance to the measurement noise covariance is a design parameter and its effect on the condition number is investigated.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.286-287
• /
• 2008

This paper proposes a power system blackout model and devises a method of identification and selection of higher-order contingencies that may threaten power system security. To study how failures spread in power grids, network observability based on topological concept is utilized which provide a means of monitoring network evolutions due to multiple contingencies. The simulations and results are presented using the IEEE 118-bus test system.

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.635-638
• /
• 1998

This paper proposes a simple method to measure system's performance in target tracking problems. Essentially employing the Cramer-Rao lower bound (CRLB) on trakcing accuracy, an algorithm of predicting system's performance under various scenarios is developed. The input data is a collection of measurements over time fromsensors embedded in gaussian noise. The target of interest may not maneuver over the processing time interval while the own ship observing platform may maneuver in an arbitrary fashion. Th eproposed approach is demonstrated and discussed through simulation results.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.35C no.11
• /
• pp.11-20
• /
• 1998

Testability analysis computes controllabilities and observabilities of all lines of a circuit and then evaluates fault coverage. The values of controllability and observability as well as fault coverage produced by testability analysis are used for applications of testability analysis. ITEM was evaluated as a fault coverage tool. But the values of controllability and observability at all lines of circuits must be estimated as a performance measure of testability tools for another application such as partial scan. In this paper, partial scan method based on sensitivity analysis which estimates relative improvement of detectability of circuits after scanning a flip-flop is used for performance evaluation of ITEM. Performance of ITEM, with respect to testability values on each net, has been measured by comparing ITEM and STAFAN. Partial scan performance achieved by ITEM is very similar to that of STAFAN, but ITEM takes less CPU time. Therefore ITEM is very efficient for partial scan application because ITEM runs faster for very large circuits in which execution time is critical.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.1
• /
• pp.448-456
• /
• 2020

This study found that it is critical to consider farmers' intention to adopt new technology in order to facilitate the spread of new technology. Based on this assumption, the research team analyzed the following: factors that influence intention of adoption and marginal effects on those factors. The data were collected from 99 farmers who did not participate in the pilot projects on dissemination of new technologies developed by the Rural Development Administration (RDA). A total of 19 observed variables were set to measure seven latent variables: educational support; technical support; funding support; compatibility; trialability; observability; and antipathy. The intention to adopt new technology was established as the dependent variable. According to the ordered logit analysis, educational support, observability, and antipathy were found to have significantly affected the intention to adopt new technology; their odds ratio were 6.938, 2.716, and 0.501, respectively. According to the marginal analysis, educational support, observability, and antipathy were found to have significantly affected the intention to adopt new technology; their marginal effects were 20.2 %, 10.4 %, and -7.2 %, respectively. Therefore, this study suggests the following to facilitate the spread of new technology: first, provide quality support services through effective deduction; second, increase the visibility of new technology; and third, enhance the credibility of agricultural institutions by developing continuous relations with farmers to reduce their antipathy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.212-215
• /
• 2003

This paper presents constitution of a moderate price thermography system for on-line measurement. All objects with some temperature above absolute zero radiate in the infrared. The intensities and spectra of the infrared radiated from some object depend on the conditions and temperature distributions on the surface of the objects, and the temperature distributions differ from each others with different undersurface structures. Consequently, infrared radiation is useful for diagnosis of the conditions on the surface and undersurface of electric power apparatus. But the present, because engineers directly measure the temperatures of apparatuses in off-line, the measured data do not always have the information of the past. The proposed system is able to analyze not only the information of the past but the trend of deterioration, and the system is able to compensate for the distortion of surface temperature as to weather conditions. The thermal image histogram is equalized to upgrade observability, and a pan-tilter is adopted to control of direction for any target point.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.36 no.10
• /
• pp.1087-1099
• /
• 2012

This study investigated the purchase intention of green fashion products based on Rogers' Diffusion of Innovation theory and compared the differences between Korean and British consumers. In order to identify the impact of personal characteristics, this study also examined the effects of fashion innovativeness and LOHAS tendency on perceived attributes of innovation and intention to purchase. With a convenience sampling method, a survey questionnaire was distributed at popular fashion streets in each country. A total of 426 data were obtained, 203 from the UK and 223 from Korea. About 52% were females, and 69% were in their twenties. A factor analysis generated two LOHAS factors (health concerns and eco concerns) and four attributes of green fashion products (image improvement, symbolic superiority, observability, and compatibility). Two types of green fashion products (organic cotton t-shirts and organic cotton t-shirts with an environmental message) were provided to measure the purchase intention, respectively. The findings were as follows. British consumers were more likely to show LOHAS tendency and to perceive positive advantages of green products compared to Koreans; in addition, British consumers presented higher mean scores on the purchase intentions of organic cotton products. Fashion innovativeness was significant to predict image improvement and symbolic superiority, while eco concerns were significant in compatibility for both nations. Compatibility was important for both countries in order to explain the intention to adopt two types of organic products. In addition, image improvement was another predictor for purchase intention of organic t-shirts with an environmental message. Managerial implications were provided.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.11
• /
• pp.997-1003
• /
• 2012

GNSS and ARS are the most common sensors in low-end UAVs. However, these sensors are vulnerable to built-in errors and cannot measure the body heading independently. The GNSS/INS cannot fully compensate the IMU errors in initial alignment process and rectilinear flights. For an unmanned helicopter, a magnetometer can be more useful than any other sensors to obtain heading information. However, the electric motor which drives small helicopter UAV keeps the magnetometer from reading the pure magnetotelluric vector. This paper shows the effects of electric motor on the magnetometer readings, and presents a method to compensate the effects. The results are verified with flight test data. The simulation and experimental results in this paper proves that aiding GNSS/INS with magnetometer increases observability and improves accuracy.