• The Journal of the Acoustical Society of Korea
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• v.16 no.2
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• pp.89-94
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• 1997

A new type SO$_2$ gas sensor with a particular inorganic thin film on SAW devices was developed. The sensor consisted of twin SAW oscillators of the center frequency of 54 MHz fabricated on the LiTaO$_3$ piezoelectric single crystal. One delay line of the sensor was coated with a CdS thin film that selectively adsorbed and desorbed SO$_2$, while the other was uncoated for use as a stable reference. Deposition of the CdS thin film was carried out by the spray pyrolysis method using an ultrasonic nozzle. The sensor could measure the concentration in air less than 0.25 parts per million of SO$_2$. Stability of the sensor turned out to be as good as less than 20ppm, recovery time after each measurement was as short as 5 minutes. Repeatability of the measurement was confirmed through so many reiterated experiments. Hence, the SAW sensor developed through this work showed promising performance as a microsensing tool of SO$_2$. Further work required to improve the performance of the sensor includes enhancement of the reactivity of the CdS thin film with SO$_2$ through appropriate dopant addition, an increase of the center frequency of the SAW device.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.2
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• pp.376-380
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• 2004

The purpose of this study is the develop a questionnaire for measuring Yin-Deficiency and examine the reliability and validity for its' value as a barometer for evaluating Yin-Deficiency. Questionnaire was developed according to the symptoms of Yin-Deficiency suggested in the 'Standardization of diagnostic terms and requirements of Korean Medicine', With and as a reference, each symptom has been worked on to be put on the questionnaire. Visual analogue scales(VAS) was used as a barometer for measuring frequency of manifestation of symptoms. A study was performed to measure validity and reliability of the final questionnaire for analysis. reliability of YinDQ was measured by Cronbach's alpha coefficient and test-retest method. This study utilized factor analysis and clinical validity for evaluation of validity. For the purpose of decreasing the amount of data-the number of factors, and at the same time minimize the loss of information factor analysis was performed Component factors were extracted using Principal Component Analysis. This study evaluated the clinical validity for examination of difference between the normal group and the patient group. Evaluation on the's internal consistency showed strong internal consistency with value of 0.8615. reliability from test-rest with three-week interval, followed by comparisons of the correlation coefficient and mean values of each item between the two. The Spearman correlation coefficient was 0.54-0.79. By factor analyse two factors with Eigen value of greater than 2.2 were selected. Factor 1 consists of items of 'irritable fever on the five Hearts', 'flushing of the zygomatic region in the afternoon', 'tidal fever', 'night sweats', and 'dryness on the mouth or the throat'. Factor two consists of items of 'emaciation', 'dizziness', 'insomnia', 'decreased amount of urine with yellowish color', and 'constipation'. The comparison between the patient group and the normal group showed significant differences for every ten questions. The results implies that YinDQ is a barometer with sufficient reliability and validity. The questionnaire for Yin-Deficiency may not be enough to replace the specific differential diagnosis by a doctor of Oriental medicine. Nevertheless, it can be effectively utilized as an assisting method in consultation or a method of measuring the degree of Yin-Deficiency in a group.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.5
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• pp.43-51
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• 2010

Attenuation coefficients of medical ultrasound not only reflect the pathological information of tissues scanned but also provide the quantitative information to compensate the decay of backscattered signals for other medical ultrasound parameters. Based on the frequency-selective attenuation property of human tissues, attenuation estimation methods in spectral domain have difficulties for real-time implementation due to the complexicity while estimation methods in time domain do not achieve the compensation for the diffraction effect effectively. In this paper, we propose the modified VSA method, which compensates the diffraction with reference phantom in time domain, using adaptive bandpass filters with decreasing center frequencies along depths. The adaptive bandpass filtering technique minimizes the distortion of relative echogenicity of wideband transmit pulses and maximizes the signal-to-noise ratio due to the random scattering, especially at deeper depths. Since the filtering center frequencies change according to the accumulated attenuation, the proposed algorithm improves estimation accuracy and precision comparing to the fixed filtering method. Computer simulation and experimental results using tissue-mimicking phantoms demonstrate that the distortion of relative echogenicity is decreased at deeper depths, and the accuracy of attenuation estimation is improved by 5.1% and the standard deviation is decreased by 46.9% for the entire scan depth.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.3
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• pp.232-242
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• 2015

For stealth performance consideration, many UAV designs are adopting tailless lambda-shaped configurations which are likely to have unsteady dynamic characteristics. In order to control such UAVs through automatic flight control system, more accurate estimation of dynamic stability derivatives becomes essential. In this paper, dynamic stability derivatives of a tailless lambda-shaped UAV are estimated through numerically simulated forced oscillation method incorporating dynamic mesh technique. First, the methodology is validated by benchmarking the CFD results against previously published experimental results of the Standard Dynamics Model(SDM). The dependency of initial angle of attack, oscillation frequency and oscillation magnitude on the dynamic stability derivatives of a tailless UAV configuration is then studied. The results show reasonable agreements with experimental reference data and prove the validity and efficiency of the concept of using CFD to estimate the dynamic derivatives.

• The KIPS Transactions:PartB
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• v.18B no.2
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• pp.51-56
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• 2011

Algorithms for intrinsic images reduce color differences in RGB images caused by the temperature of black-body radiators. Based on the reference light and detecting single invariant direction, these algorithms are weak in real images which can have multiple invariant directions when the scene illuminant is a colored illuminant. To solve these problems, this paper proposes a method of acquiring an intrinsic image by omnidirectional projection of an ROI and a translation of white patch in the ${\chi}$-chromaticity space. Because it is not easy to analyze an image in the three-dimensional RGB space, the ${\chi}$-chromaticity is also employed without the brightness factor in this paper. After the effect of the colored illuminant is decreased by a translation of white patch, an invariant direction is detected by omnidirectional projection of an ROI in this chromaticity space. In case the RGB image has multiple invariant directions, only one ROI is selected with the bin, which has the highest frequency in 3D histogram. And then the two operations, projection and inverse transformation, make intrinsic image acquired. In the experiments, test images were four datasets presented by Ebner and evaluation methods was the follows: standard deviation of the invariant direction, the constancy measure, the color space measure and the color constancy measure. The experimental results showed that the proposed method had lower standard deviation than the entropy, that its performance was two times higher than the compared algorithm.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.323-334
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• 2008

This experiment was carried out to analyze for pesticide residues in 17 different types of the special of geographical indication. We purchased 3 cereal grains, nuts and seeds, 3 fruits, 8 vegetables, mushrooms and other plants (Korean medicines) mainly at the agricultural cooperative's joints markets. Total 209 pesticides including multi-analysed pesticides (204) and single-analysed pesticides (5 ; acephate, methamidophos, monocrotophos, omethoate, vamidothion) were analysed with a GC/MS/MS, an HPLC/UVD (PDA) and a GC/FPD. No. 83 method and single-analysed method (Screening of multi-pesticide residue in the special products of geographical indication) of Korea Food Code was selected for validation in recovery and interferences of matrice. The results were as follows: among the selected 17 the special products, the residual pesticides were detected in 8 types of the special products (40 in 302 samples, detection ratio; 13.2%). All of the samples were not detected over MRLs, but tebuconazole, procymidone and isoprothioran were detected with considerable high frequency. These results could be used as KFDA official methods for the analysis of pesticide residues in foods and reference data will be provided to the related institutions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1423-1433
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• 2018

Recently, a permanent magnet synchronous motor of middle and small-capacity has high torque, high precision control and acceleration / deceleration characteristics. But existing control has several problems that include unpredictable disturbances and parameter changes in the high accuracy and rigidity control industry or nonlinear dynamic characteristics not considered in the driving part. In addition, in the drive method for the control of low-vibration and high-precision, the process of connecting the permanent magnet synchronous motor and the load may cause the response characteristic of the system to become very unstable, to cause vibration, and to overload the system. In order to solve these problems, various studies such as adaptive control, optimal control, robust control and artificial neural network have been actively conducted. In this paper, an incremental encoder of the permanent magnet synchronous motor is used to detect the position of the rotor. And the position of the detected rotor is used for low vibration and high precision position control. As the controller, we propose augmented state feedback control with a speed observer and first order deadbeat disturbance observer. The augmented state feedback controller performs control that the position of the rotor reaches the reference position quickly and precisely. The addition of the speed observer to this augmented state feedback controller compensates for the drop in speed response characteristics by using the previously calculated speed value for the control. The first order deadbeat disturbance observer performs control to reduce the vibration of the motor by compensating for the vibrating component or disturbance that the mechanism has. Since the deadbeat disturbance observer has a characteristic of being vulnerable to noise, it is supplemented by moving average filter method to reduce the influence of the noise. Thus, the new controller with the first order deadbeat disturbance observer can perform more robustness and precise the position control for the influence of large inertial load and natural frequency. The simulation stability and efficiency has been obtained through C language and Matlab Simulink. In addition, the experiment of actual 2.5[kW] permanent magnet synchronous motor was verified.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.1009-1019
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• 2009

In this research, various characteristics of South Korea's design flood have been examined by deriving appropriate design flood, using data obtained from careful observation of actual floods occurring in selected main watersheds of the nation. 19 watersheds were selected for research in Korea. The various characteristics of annual rainfall were analyzed by using a moving average method. The frequency analysis was decided to be performed on the annual maximum flood of succeeding one year as a reference year. For the 19 watersheds, tests of basic statistics, independent, homogeneity, and outlier were calculated per period of annual maximum flood series. By performing a test using the LH-moment ratio diagram and the Kolmogorov-Smirnov (K-S) test, among applied distributions of Gumbel (GUM), Generalized Extreme Value (GEV), Generalized Logistic (GLO) and Generalized Pareto (GPA) distribution was found to be adequate compared with other probability distributions. Parameters of GEV distribution were estimated by L, L1, L2, L3 and L4-moment method based on the change in the order of probability weighted moments. Design floods per watershed and the periods of annual maximum flood series were derived by GEV distribution. According to the result of the analysis performed by using variation rate used in this research, it has been concluded that the time for changing the design conditions to ensure the proper hydraulic structure that considers recent climate changes of the nation brought about by global warming should be around the year 2002.

• Journal of Korean Library and Information Science Society
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• v.9
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• pp.241-266
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• 1982

This paper gives a summary and overview of a survey conducted at the catalogues of five universities in Daegu during November 1982. The major objective of this study was to secure information about user needs in order to improve the catalogue in Korean university libraries. Data was collected by a combined method of questionnaire and interview. A total of 379 respondents were taken on a randomly selected sample of catalogue users. Results of the survey can be summarized as follows: 1. Eighty-eight percent of the students answered that they had used the library more than twice a month. Nevertheless the number of students consulting the catalogue with the same frequency was only 220, or a n.0, pproximately 58 percent. Those who used the library most tended to use the catalogue more than those who rarely came to the library. 2. Those who had been shown how to use their own catalogue were only 32.5percent of which the students found the instruction sufficient for them to be able to use the catalogue were only 37.5 percent. In particular, they stated that instructions by printed materials and/or library orientation were so poor that they didn't give much help in using the catalogue. This problem makes many libraries to review their own method of instruction in order to encourage patrons to use the catalogue more effectively. 3. Most of the students consulted the catalogue in order to locate library materials. Known-item searches and subject searches were 84 and 16 percent respectively. While 70.5 percent of the students used the author-title catalogue without any difficulties, only 35.5 percent of those stated that using the classed catalogue was easy. 4. It was surprising that the number of students using title access in the search was far greater than that of students using author access. In contrast with this, other studies conducted by many earlier overseas investigators revealed that the great majority of patrons tended to use the latter first. Therefore, we should put more emphasis on the title entries in the catalogue itself as well as cataloging rules. 5. Most useful bibliographic elements in the entry were author, title, call number, date and publisher whereas edition, series statement and the location of publisher were rarely used compared with the other elements. Content note was the most desirable element in the entry to be involved, for many catalogers were used not to describe it on the note area. 6. The chief reason given for not using the catalogue was "I can manage without it" with "It's difficult to understand contents of the card entry." The other one was "It's useless to search materials by the catalogue because I've failed so many times to obtain them out of the stock." In response to this, circulation and acquisition system should be improved not to make such complaints any more.

• Journal of Home Health Care Nursing
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• v.12 no.1
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• pp.92-116
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• 2005

Purpose: This study was a predicative survey to provide home care clients with indwelling urinary catheters for furnishing basic educational material to their families by analyzing the family members' knowledge, educational needs and educational experience about indwelling catheter management. Method : The subjects consisted of 108 family members who cared for home care clients with indwelling catheters. Data were collected by home care nurses in nine hospitals in Pusan, who directly interviewed with them through questionnaires from Sep. 6th to 30th in 2004. The questionnaires for data collection were developed through pre-survey and reference review. The collected data was analyzed by using frequency, percentile, mean, variation, t-test, ANOVA on SPSS 10.1 package. Results : There were characters of home care clients with indwelling catheters: women(67.6%) were more than men; the average age of them was $69.60{\pm}14.99$ years old; neurogenic and cerebrovascular diseases(80.0%) were the most common disease group; 81.5% of them were totally dependent on others in terms of level of activity. Home care clients' families had these characters: women(76.9%) were more than men; the average age was $54.5{\pm}13.70$ years old; 46.3% of them were parents or sons or daughters in terms of relation with patient; tl1e average care period was $39.8{pm}34.20$ months. Level of knowledge about indwelling catheter management of the family members were 69.8% and its mean were $20.24{\pm}4.53$. Educational needs were 90.9% and its mean were $14.55{\pm}3.56$. Educational experience were 53.3% and its mean were $8.53{\pm}4.30$. 'Complications in using an indwelling catheter', 'Symptoms to call for a home care nurse' and 'Method to attach an indwelling catheter' were high ranked in both educational needs and educational experience. 'Anatomy of urinary tract', 'Functions of urinary tract' and 'Catheter placement' were low ranked in both educational needs and educational experience Level of knowledge about indwelling catheter management of the families showed a significant difference according to their age(F=5.35, p=0.01). Educational needs showed a significant difference according to care period(F=3.06, p=0.04). Conclusion: the family members' level of knowledge and educational experience about indwelling catheter management and their educational were not sufficient while their educational needs were high. In other words although the family members were acknowledged education needs, but the care for the patients with indwelling catheter weren't performed well because of their lack of related knowledge. Therefore systematic educational programs about indwelling catheter management for home care clients and their families should be made on the base of this study.