• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.7
• /
• pp.537-544
• /
• 2007

To facilitate comparative analysis on the effects of numerous parameters concerning design and operation of a desiccant rotor, it is firstly required to represent the dehumidification performance as numerical indices. In this work is proposed two performance indices of a desiccant rotor: the humidity effectiveness and the enthalpy-leak ratio. The humidity effectiveness represents the actual dehumidification as compared with the dehumidification in an ideal case, while the enthalpy-leak ratio represents the enthalpy transfer from the regeneration side to the dehumidification side. In an ideal case, the two indices approach one and zero, respectively. The effects of numerous parameters on the dehumidification performance of a desiccant rotor are investigated through numerical simulation and represented with the two indices. The results show that the performance indices are mainly determined by three nondimensional parameters each representing the thermal capacity, the sorption capacity, and the transfer capacity of a desiccant rotor.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.10 no.6 s.52
• /
• pp.47-56
• /
• 2006

A method is presented for evaluating the economic efficiency of a semi-active magneto-rheological (MR) damper system for cable-stayed bridges under earthquake loadings. An optimal MR damper capacity maximizing the cost-effectiveness is estimated for various seismic characteristics of ground motion. The economic efficiency of MR damper system is addressed by introducing the life-cycle cost concept. To evaluate the expected damage cost, the probability of failure is estimated. The cost-effectiveness index is defined as the ratio of the sums of the expected damage costs and each device cost between a bridge structure with the MR damper system and a bridge structure with elastic bearings. In the evaluation of cost-effectiveness, the scale of damage cost is adopted as parametric variables. The results of the evaluation show that the MR damper system can be a cost-effective design alternative. The optical capacity of MR damper is increased as the seismic hazard becomes severe.

• Journal of Navigation and Port Research
• /
• v.34 no.1
• /
• pp.83-89
• /
• 2010

By analyzing the data collected through surveys conducted on coast guard officers, this paper measures the level of organizational health and explores indicators of organizational health that influence organizational effectiveness. The findings of the analysis can be summarized as follows: First, the scores of all the organizational health indicators except job stress exceed average, which leads a conclusion that coast guard organizations' organizational health is in considerably good condition. Second, the indicators of organizational health included in the analyses are found to have both positive and negative effects on organizational effectiveness. While such variables as pay, co-worker relationship, job autonomy, job itself, organizational trust, job orientation influence positively, other variables including development-oriented culture, promotion system and supervision influence negatively on organizational effectiveness.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.30 no.3
• /
• pp.29-39
• /
• 2017

Objectives: The purpose of this study is to investigate the effectiveness of acupuncture and moxibustion for mastitis. Methods: We used ten databases including Embase, PubMed, and CNKI to investigate the literatures of mastitis using the keywords "mastitis" and "acupuncture", "breast inflammation" and "acupuncture", "mastitis" and "needle", "breast inflammation" and "needle", "mastitis" and "moxibustion". We excluded studies which included treatments that could affect the judgement of the effectiveness of acupuncture treatment, and the control group was limited to antibiotics. The quality of the paper was evaluated by Risk of Bias. A meta-analysis was performed using a "Review manager" to see the effectiveness of acupuncture and moxibustion compared to antibiotics. Results: Only six RCT were finally selected. Five studies use the total effective rate as a evaluating index, and it was significantly higher than that of the control group in two studies. In other three studies, acupuncture showed similar effectiveness to antibiotics. Meta-analysis was performed through three studies, there was no statistically significant difference in total effective rate between acupuncture and antibiotic treatment. Conclusions: Analysis of six RCT showed that acupuncture and moxibustion seem to have many possibilities as one of the treatments for mastitis. However the number of documents is not sufficient, more research should be done to obtain reliable information.

• Healthcare Informatics Research
• /
• v.24 no.4
• /
• pp.346-358
• /
• 2018

Objectives: The association between obstructive sleep apnea (OSA) and mortality or serious cardiovascular events over a long period of time is not clearly understood. The aim of this observational study was to estimate the clinical effectiveness of continuous positive airway pressure (CPAP) treatment on an outcome variable combining mortality, acute myocardial infarction (AMI), and cerebrovascular insult (CVI) during a follow-up period of 15.5 years ($186{\pm}58$ months). Methods: The data set consisted of 978 patients with an apnea-hypopnea index (AHI) ${\geq}5.0$. One-third had used CPAP treatment. For the first time, a data-driven causal Bayesian network (DDBN) and a hypothesis-driven causal Bayesian network (HDBN) were used to investigate the effectiveness of CPAP. Results: In the DDBN, coronary heart disease (CHD), congestive heart failure (CHF), and diuretic use were directly associated with the outcome variable. Sleep apnea parameters and CPAP treatment had no direct association with the outcome variable. In the HDBN, CPAP treatment showed an average improvement of 5.3 percentage points in the outcome. The greatest improvement was seen in patients aged ${\leq}55$ years. The effect of CPAP treatment was weaker in older patients (>55 years) and in patients with CHD. In CHF patients, CPAP treatment was associated with an increased risk of mortality, AMI, or CVI. Conclusions: The effectiveness of CPAP is modest in younger patients. Long-term effectiveness is limited in older patients and in patients with heart disease (CHD or CHF).

• Journal of the Optical Society of Korea
• /
• v.7 no.4
• /
• pp.234-239
• /
• 2003

Objective methods to assess quantitatively port wine stain (PWS) blanching in response to laser therapy are needed to improve laser therapeutic outcome. Previous studies have attempted to assess objectively PWS color based on point measurement devices. To date, these approaches have typically been limited by a number of factors such as small test area and need for contact. To address these issues, a polarization spectral imaging system and an image analysis method have been developed to evaluate quantitatively erythema and melanin content distribution in skin. The developed polarization spectral imaging system minimizes artifacts such as glaring, shadowing, and non-uniform illumination that interfere with image fidelity. Furthermore, the image analysis method has been employed to get images of skin melanin and erythema indices from the acquired color images for quantitative analysis. Finally, using PWS patient color image, the effectiveness in laser treatment of PWS was evaluated by calculating relative erythema index image that is the relative erythema index of PWS region to the normal region. The developed device and analysis method appears to be a simple and effective method for quantitative analysis of PWS blanching.

• Journal of Institute of Control, Robotics and Systems
• /
• v.15 no.6
• /
• pp.581-589
• /
• 2009

In a two-inertia motor system with flexible shaft, a torsional vibration is often generated as a quick speed response is required. This vibration makes it difficult to achieve a quick response of speed and disturbance rejection. The objective of this paper is to provide a systematic analysis and design of the three kinds of speed controllers such as I-P, I-PD, and state feedback control by using the weighted ITAE performance index. Some simulation and experiment results verify the effectiveness of the proposed design.

• Journal of the Korean Society for Library and Information Science
• /
• v.9
• /
• pp.99-118
• /
• 1982

This paper first reviews various techniques proposed for automatic indexing with special emphasis placed on statistical techniques. Frequency-based statistical techniques are categorized into the following three approaches for further investigation on the basis of index term selection criteria: term frequency approach, document frequency approach, and probabilistic approach. In the experimental part of this study, Pao's technique based on the Goffman's transition region formula and Harter's 2-Poisson distribution model with a measure of the potential effectiveness of index term were tested. Experimental document collection consists of 30 agriculture-related documents written in Korean. Pao's technique did not yield good result presumably due to the difference in word usage between Korean and English. However, Harter's model holds some promise for Korean document indexing because the evaluation result from this experiment was similar to that of the Harter's.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.736-742
• /
• 2008

This paper proposes new searching algorithm for the optimal PD gains of flexible rotor supported by active magnetic bearings. Under the assumption of linearized bearing parameters with respect to PD gains, the performance index in quadratic form is defined and steepest descent method is adopted for determining local minimum. Moreover, the eigenpair sensitivity concept is utilized to evaluate the sensitivity of performance index. To evaluate the effectiveness of suggested algorithm, the finite element model is constructed and its reduced model is retained in modal domain. Given starting gains, the optimal gains are successfully found and the control performance is demonstrated by simulation to show the efficiency of the proposed method.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.41 no.2
• /
• pp.17-33
• /
• 2016

Clustering is one of the leading methods to analyze big data and is used in many different fields. This study deals with Clustering Validity Index (CVI) to verify the effectiveness of clustering results. We compare the performance of CVIs with business applications of various field. In this study, the used CVIs for comparing performance are DU, CH, DB, SVDU, SVCH, and SVDB. The first three CVIs are well-known ones in the existing research and the last three CVIs are based on support vector data description. It has been verified with outstanding performance and qualified as the application ability of CVIs based on support vector data description.