• Journal of Korean Society for Quality Management
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• v.12 no.2
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• pp.6-10
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• 1984

A model for obtaining optimal resetting period and optimal target value of the process quality level is proposed when the quality characteristic is subject to a linear shift in mean. Different sales conditions are considered where good items can he sold at a regular price and bad items at a discounted one. Some numerical examples are also given.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.550-561
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• 2019

Objectives: The purpose of this study is to provide basic data for the improvement of the working environment for health prevention and related countermeasures for shift workers. This study was conducted based on the Fifth Korean Working Conditions Survey (KWCS), which analyzed the health effects of shift work forces and compared them with preceding studies. Methods: By analyzing secondary rates using raw data from the 5th KWCS, 4,870 (9.7%) of the 50,184 total study subjects were divided into shift work and 45,314 (90.3%) non-shift work groups based on the response to shift status. Variables that could affect work health issues were identified and corrected. A cross-analysis was conducted to examine demographic characteristics (gender, age, and education level) of the workers and occupation characteristics (monthly net earnings, employment type, occupation, working period up to now, workplace scale, type of work system, and weekly working hours). In order to find the work health issue ratio between the shift and non-shift work groups, logistic regression was analyzed and the association with health problems according to shift type by gender was looked at through cross-analysis. Results: According to the surveys conducted from the 1st KWCS (2006) to the 5th KWCS (2017), the proportion of shift workers continued to increase. Also, muscular pains in the lower limbs (hips, legs, knees, feet, etc.) (OR=1.135, 95%CI 1.031-1.251), headaches, eyestrain (OR=1.580, 95% CI 1.428-1.748), anxiety (OR=1.715, 95% CI 1.402-2.099), difficulty falling asleep (OR=1.391), and other problems (OR=7.392) were reported. In addition, back pain, muscular pains in shoulders, neck and/or upper limbs, muscular pains in lower limbs (hips, legs, knees, feet, etc.), headaches, eyestrain, depression, anxiety, overall fatigue resulted in significant results for both male and female shift workers. Depression and anxiety were higher in female shift/circulation compared to males. Conclusions: The social nets for the health and safety of shift workers should be explored in a variety of ways, including management and supervision of shift sites, attempts to reorganize and improve the shift system, development of workers' health recovery programs, promotion, systematic treatment, and compensation systems.

• The KIPS Transactions:PartB
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• v.17B no.1
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• pp.15-22
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• 2010

Background generation is very important for accurate object tracking in video surveillance systems. Traditional background generation techniques have some problems with non-moving objects for longer periods. To overcome this problem, we propose a newbackground generation method using mean-shift and Fast Marching Method (FMM) to use pixel information along temporal and spatial dimensions. The mode of pixel value density along time axis is estimated by mean-shift algorithm and spatial information is evaluated by FMM, and then they are used together to generate a desirable background in the existence of non-moving objects during longer period. Experimental results show that our proposed method is more efficient than the traditional method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.1
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• pp.110-117
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• 2018

Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. By the result of degeneration, non-conforming products and malfunction of machine occur. Therefore a periodic preventive resetting the process is necessary. This type of preventive action is called 'preventive maintenance policy.' Preventive maintenance presupposes that the preventive (resetting the process) cost is smaller than the cost of failure caused by the malfunction of machine. The process mean shift problem is a field of preventive maintenance. This field deals the interrelationship between the quality cost and the process resetting cost before machine breaks down. Quality cost is the sum of the non-conforming item cost and quality loss cost. Quality loss cost is due to the deviation between the quality characteristics from the target value. Under the process mean shift, the quality cost is increasing continuously whereas the process resetting cost is constant value. The objective function is total costs per unit wear, the decision variables are the wear limit (resetting period) and the initial process mean. Comparing the previous studies, we set the process variance as an increasing concave function and set the quality loss function as Cpm+ simultaneously. In the Cpm+, loss function has different cost coefficients according to the direction of the quality characteristics from target value. A numerical example is presented.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.619-627
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• 2020

This study measures the relationship between labor productivity and national competitiveness. Through the shift- share analysis method, the paper has separated labor productivity into three factors: static shift effect, dynamic shift effect and endogeneous effect. Next, in combination with the Granger causality test, the paper examines the relationship between the factors constituting labor productivity and competitiveness during the period from 2005 to 2017. Research data is collected from General Statistics Office and annual global competitiveness reports. The results show that the interaction between labor productivity with global competitiveness index (GCI) in Vietnam has similar variation. Nevertheless, when separating labor productivity into three effects, this relationship shows more clearly that the impact of labor productivity on GCI scores is mainly caused by endogeneous effect, not by static shift effect or dynamic shift effect. Therefore, in order to improve its competitiveness, Vietnam should focus on a number of solutions: reforming the education system towards developing thinking capacity and creative capacity; fostering industrial manners to create dynamic and flexible workers; building the State with sufficient capacity to implement consistent and transparent policies; formulating policies to attract all economic sectors so that they actively participate in the field of human resource training for the country.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.152-156
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• 2009

This paper examines the BER performance of the recently proposed half-symbol-rate-carrier (HSRC) offset quadrature phase-shift-keying (OQPSK) receiver for high-speed data communication. A modified demodulation technique using a bit-time period signal integration, the bit-error-rate (BER) performance of the HSRC-OQPSK signal improves more than 4dB compared to that of a demodulation technique using a symbol-time period integration. This paper also examines the BER performance of modified demodulation with various band-limited channels modeled using low-pass filters, and the three different data-rate systems are simulated and compared with the performance of the system using the conventional demodulation technique.

• ETRI Journal
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• v.28 no.6
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• pp.739-744
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• 2006

In this paper, we report numerically calculated results of testing a temperature-insensitive refractive sensor based on a planar-type long-period waveguide grating (LPWG). The LPWG consists of properly chosen polymer materials with an optimized thermo-optic coefficient for the core layer in a four-layer waveguide structure. The resonant wavelength shift below the spectral resolution of the conventional optical spectrum analyzer is obtained accurately over a temperature change of ${\pm}7.5^{\circ}C$ even without any temperature control. The refractive index sensitivity of the proposed grating scheme is about 0.004 per resonant wavelength shift of 0.1 nm for an optimized thermo-optic coefficient.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.61-64
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• 2000

There are many methods of generating PN sequences. In this paper, we propose and examine a new class of composite shift register to generate PN sequences. The new composite generator, in comparison with the original LFSR which generates PN codes of period 2$^n$-1, when coupled with codes of period k, generates PN codes with (longer) period LCM(2$^n$-1,k).

• Journal of Korean Biological Nursing Science
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• v.20 no.3
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• pp.187-195
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• 2018

Purpose: The purpose of this study was to identify associations among the sleep disturbance, fatigue, job stress, and blood and body fluid (BBF) exposure of shift-work nurses. Methods: A total of 299 shift-work nurses from two tertiary hospitals were enrolled in this study. We used the Insomnia Severity Index (ISI), and the Fatigue Severity Scale (FSS), and the Korean Occupational Stress Scale-Short Form (KOSS-SF) to evaluate sleep disturbance, fatigue, and job stress, respectively. The data were analyzed using t-test or chi-squared test and Logistic regression analysis using the SPSS 23.0 program. Results: We found that 43.8% of participants reported BBF exposure over the past year. Splash or exposure to broken skin of BBF were most frequent (56.9%), and followed by needlestick injuries (30.4%) and sharp injuries (12.8%). Age, hospital, working period, level of stress, sleep disturbance ($ISI{\geq}15$), fatigue (FSS $score{\geq}4$), job demand and organizational climate subset in KOSS-SF were significantly associated with BBF exposure in shift-work nurses. In multivariate analysis after adjusting age and hospital, the risk factors of BBF exposure in shift-work nurses were the level of stress and fatigue (FSS $score{\geq}4$). Conclusion: Fatigue and job stress were related to BBF exposure in shift-work nurses. Our results suggest that management of sleep disturbance, fatigue, and high job stress in shift-work nurses is needed to reduce risk of BBF exposure.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.1
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• pp.279-282
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• 2012

Background: Although more than two third of colorectal cancers are localized on the left side, recent studies suggest a right ward shift in anatomical distribution with increase in proximal colon cancers. The aim of the present study was to determine the anatomical distribution of colorectal cancer in a referral center over a 15 year period. Method: Records of patients who underwent colectomy in the Cancer Institute of Iran from 1994 to 2009 were retrieved. Data including anatomical localization, year of diagnosis, patient age and gender, tumor histology and differentiation, and disease stage were extracted. Tumors located from the cecum to the distal transverse colon were classified as right side and those occurring from the splenic flexure to the descending colon as left-sided. Cancer of rectum and recto-sigmoid junction were considered as rectal cancers. Results: A total of 442 patients including 220 (49/8%) men and 222 (50/2%) women with mean age 53 were included. Most patients were in stage II &III (47.1% and 33% respectively). There were 157 (35.5 %) colon cancers and 285 (64.5%) rectal cancers. 43.3% of the colon cancers were right sided and 56.7% were left sided. There was no statistically significant increase in right sided cancer during the period of the study. There were no significant differences in age at diagnosis, gender, grade and stage of tumor between the right and the left sided cancers. Conclusion: No proximal shift over time was identified in our study.