• 한국경영과학회지
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• 제31권4호
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• pp.1-11
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• 2006

A citation-based method of estimating the life span of a patented technology is proposed In this study. The suggested framework Includes : (1) estimation of citation frequency of an individual patent within a technology group. (2) calculation of a mutual citation frequency between citing patent and cited patents, (3) calculation of the period for cited patents from the year of registration to the year of being cited most recently and (4) description for technology group using descriptive statistics such as mean, median, mode, etc. The framework suggested in this study was applied to the US patent data between 1976 and 2004 for 5 communications areas.

• 대한산업공학회지
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• 제31권1호
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• pp.1-9
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• 2005

This paper proposes the heuristic algorithm for the generalized GT problems to consider the restrictions which are given the number of machine cell and maximum number of machines in machine cell as well as minimum number of machines in machine cell. This approach is split into two phase. In the first phase, we use the similarity coefficient which proposes and calculates the similarity values about each pair of all machines and sort these values descending order. If we have a machine pair which has the largest similarity coefficient and adheres strictly to the constraint about birds of a different feather (BODF) in a machine cell, then we assign the machine to the machine cell. In the second phase, we assign parts into machine cell with the smallest number of exceptional elements. The results give a machine-part grouping. The proposed algorithm is compared to the Modified p-median model for machine-part grouping.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 추계학술발표논문집
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• pp.1010-1013
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• 2009

본 논문에서는 STFT을 이용한 이두박근의 근전도 신호 근피로도 측정 방법을 제시한다. 개선된 STFT방식은 기존연구에서 사용되어져 왔던 중간주파수를 이용한 근피로도 측정 방법과 달리 STFT를 이용한 시간, 주파수 평면에서 2차원 영상을 이용하여 근피로도를 측정할 수 있는 방법이다. 제안한 방법은 이두박근에서 수집한 근전도 신호의 근피로도 측정에 사용하여 제안한 방법의 타당성을 검증하였다.

• 대한전기학회논문지:전력기술부문A
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• 제48권10호
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• pp.1335-1343
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• 1999

This paper presents concrete pattern recognition method to identify the strength of concrete by evidence accumulation with multiple parameters based on artificial intelligence techniques. At first, zero-crossing(ZCR), mean frequency(MEANF), median frequency(MEDF) and autoregressive model coefficient(ARC) are extracted as feature parameters from ultrasonic signal of concrete. Pattern recognition is carried out through the evidence accumulation procedure using distance measured with reference parameters. A fuzzy mapping function is designed to transform the distances for the application of the evidence accumulation method. Results are presented to support the feasibility of the suggested approach for concrete pattern recognition.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.617-620
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• 1999

In this paper, a new autofocusing technique which is resistive to noise generated by the CCD of video cameras is proposed. In the proposed scheme, the frequency selective weighted median (FSWM) filter is utilized to estimate the degree of focus and the fast hill-climbing search (HCS) strategy is exploited to determine the best focused image. Since the FSWM filter can not only extract high frequency components from the image, but also eliminate impulsive noise, the proposed autofocusing method employing the FSWM criterion function can estimate the degree of focus precisely. Furthermore, the proposed real-time HCS algorithm enables the video camera to continuously focus on dynamic images. Experimental results demonstrate that the proposed technique outperforms existing techniques by enhancing the accuracy of the focus value of the video camera without the influence of noise.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.181-188
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• 2002

It is well known that double integration of measured acceleration records are very difficult, particularly in the case of measurements on civil engineering structures. The measured accelerations on civil structures usually contain non-gaussian and low-frequency noises as well as acceleration records are non-stationary. For this type of signals, wavelet transform can be useful because of its inherent processing abilities for non-stationary signals. In this paper, the do-noising algorithm using the wavelet transform are slightly extended to process non-gaussian and low frequency noises, using median filter concepts. The example studies show that the integration can be improved using proposed method.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.6-9
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• 1996

In this paper, we attempted to analyze the contraction patterns of elbow flexor muscle during isometric, concentric and eccentric contraction. The analysis parameters are consisted of Sequency domain parameters (mean frequency, median frequency, skewness, kurtosis) and time domain parameters (zero crossing, positive maxima, integrated EMG). As a results, the analysis parameters have specific trends for muscles, muscle contraction patterns, muscle contraction angles. Especially, at the time domain analysis, IEMG is a dominant parameter for analysis of activation patterns, and the skewness, kurtosis are useful parameters for functional recognition.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제21권2호
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• pp.101-110
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• 2018

Purpose: Functional constipation (FC) is a common gastrointestinal (GI) problem affecting children's well-being and quality of life. Although polyethylene glycol (PEG) is recommended as the first line therapy, it is not always applicable in lower socioeconomic populations. Hence, this study aimed to compare clinical courses of FC in children treated with different medications in order to identify prognostic factors related to treatment outcomes. Methods: We reviewed the medical records of patients aged ${\leq}15$ years diagnosed with FC according to the Rome IV criteria from 2007 to 2015 at the GI clinic, Songklanagarind Hospital. Baseline characteristic, medical history, and treatment outcomes were collected at first and subsequent visits. Results: Exactly104 patients (median age at diagnosis, 2.8 years) were diagnosed with FC. The number of follow-up visits per patient ranged from 1 to 35. The median duration of follow-up was 18.0 months (range, 6.0-84.2 months). PEG was given to 21% of patients. During the follow up period, 76% of patients experienced first recovery with a median time to recovery of 9.8 months. There were no significant differences in time until first recovery and relapse between patients who received and those who did not receive PEG (p=0.99 and 0.06, respectively). Age >6 years, normal defecation frequency, no history of cow's milk protein allergy, and use of laxatives were associated with successful outcomes. Conclusion: Treatment outcomes between patients who had and never had PEG demonstrated no significant difference in our study. Hence, current practices in laxative prescriptive patterns may be effective.

• Clinical and Experimental Pediatrics
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• 제58권4호
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• pp.129-135
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• 2015

Purpose: This study investigated the long-term clinical outcomes of patients with $p22^{phox}$-deficient chronic granulomatous disease (CGD) on Jeju Island and retrospectively evaluated the effects of interferon-gamma (IFN-${\gamma}$) prophylaxis. Methods: The medical records of 15 patients with CGD were retrospectively reviewed. The efficacy of IFN-${\gamma}$ prophylaxis was evaluated by comparing the frequency of severe infections before and after starting continuous prophylaxis with IFN-${\gamma}$. Results: At the time of the analysis, 14 patients were alive, with a median age of 14.3 years. The diagnosis of CGD was made at a median age of 2.4 years, and the median age at onset of severe infection was 0.3 years. Thirteen of the 15 patients had their first severe infection within the first year of life. The overall incidence of severe infection was 1.36 infections per patient-year; pneumonia, suppurative lymphadenitis, and skin and subcutaneous abscesses were the most common infections. Aspergillus species were the most frequently isolated microorganisms, present in 15.8% of isolates. IFN-${\gamma}$ did not significantly change the rate of severe infection. The survival rate for patients after 2 years of age was 93%; there was a prolonged survival plateau beyond the age of 2. Conclusion: Compared with cases of X-linked CGD reported in other studies, patients with CGD on Jeju Island did not show obviously different clinical manifestations, but they had a significantly higher survival rate. Further studies with a substantially longer period of observation, and with more patients under intensive surveillance are necessary to elucidate the prophylactic efficiency of IFN-${\gamma}$.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제18권4호
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• pp.238-245
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• 2015

Purpose: The aim of this study was to evaluate bolus transit during esophageal swallow (ES) and gastroesophageal reflux (GER) events and to investigate the relationship between the characteristics of ES and GER events in a population of term and preterm newborns with symptoms of gastroesophageal reflux disease (GERD). Methods: The study population consisted of term and preterm newborns referred to combined multichannel intraluminal impedance (MII) and pH monitoring for GERD symptoms. The frequency and characteristics of ES and GER events were assessed by two independent investigators. Statistical significance was set at p<0.05. Results: Fifty-four newborns (23 preterm) were included in the analyses. Median bolus head advancing time corrected for esophageal length (BHATc) was shorter during mealtime than during the postprandial period (median, interquartile range): 0.20 (0.15-0.29) s/cm vs. 0.47 (0.39-0.64) s/cm, p<0.001. Median bolus presence time (BPT) was prolonged during mealtime: 4.71(3.49-6.27) s vs. 2.66 (1.82-3.73) s, p<0.001. Higher BHATc (p=0.03) and prolonged BPT (p<0.001) were observed in preterm newborns during the postprandial period. A significant positive correlation between BHATc and bolus clearance time was also observed (${\rho}=0.33$, p=0.016). Conclusion: The analysis of ES and GER events at the same time by MII provides useful information to better understand the physiopathology of GERD. In particular, the analysis of BHATc during the postprandial period could help clinicians identify newborns with prolonged esophageal clearance time due to impaired esophageal motility, which could allow for more accurate recommendations regarding further tests and treatment.