• The Journal of Korean society of community based occupational therapy
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• v.6 no.2
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• pp.11-20
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• 2016

Objective : The objective of this study was to evaluate the effects of rehabilitation therapists' general characteristics and job involvement on stress. The subjects of this study were occupational therapists and physical therapists working for long-term hospitals and general hospitals located in K and B cities, South Korea. Methods : The study investigated general characteristics, job stress, and job involvement by using questionnaires. Analysis conducted on total 144 questionnaires excluding 19 questionnaires, which did not satisfy the subject selection criteria. Results : The results show that job involvement had significantly positive correlations with job requirement, job autonomy, relationship conflicts, organization system, inappropriate compensation, job instability, and workplace culture. Secondly, marital status, wage level, and job engagement explained 46.6% of variations in job stress. Conclusion : The study was meaningful in examining the variables influencing the job stress of rehabilitation therapists. We expect that it can be used for improving the job environment of rehabilitation therapists.

• Journal of Navigation and Port Research
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• v.31 no.5 s.121
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• pp.409-414
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• 2007

The effect of multipath is especially serious in urban area and sea surface where buildings and water reflect GPS signal. Multipath brings about the performance degradation on many GPS application because the presence of multipath causes the diminution of pseudorange measurement accuracy in turn position accuracy. In this paper, a multipath mitigation named weighted correlation method is implemented on software GPS receiver, in which the asymmetric correlation function is compensated by modifying the late correlation value. Asymmetry compensation is obtained as weighted sum of two correlators which have different early-late chip spaces. This structure is adopted to lessen the computation load lower keeping up performance similar to that. The performance of implemented multipath mitigation technique is evaluated using GPS signal and multipath signal generated by GPS signal generator and software GPS receiver. The test results show that the weighted correlation method gives hefter performance than the standard correlator and the narrow correlator.

• Journal of KIISE:Software and Applications
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• v.35 no.1
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• pp.1-11
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• 2008

This paper detected the characteristics of motion vector to support efficient content -based video search of video. Traditionally, the present frame of a video was divided into blocks of equal size and BMA (block matching algorithm) was used, which predicts the motion of each block in the reference frame on the time axis. However, BMA has several restrictions and vectors obtained by BMA are sometimes different from actual motions. To solve this problem, the foil search method was applied but this method is disadvantageous in that it has to make a large volume of calculation. Thus, as an alternative, the present study extracted the Spatio-Temporal characteristics of Motion Vector Spatio-Temporal Correlations (MVSTC). As a result, we could predict motion vectors more accurately using the motion vectors of neighboring blocks. However, because there are multiple reference block vectors, such additional information should be sent to the receiving end. Thus, we need to consider how to predict the motion characteristics of each block and how to define the appropriate scope of search. Based on the proposed algorithm, we examined motion prediction techniques for motion compensation and presented results of applying the techniques.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.11 no.1
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• pp.53-64
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• 2016

Objectives : The aim of this study is to assess the usage of diagnosis codes for somatic dysfunctions and the general characteristics of patients diagnosed with the code, by analyzing health insurance data provided by the Health Insurance Review & Assessment Service(HIRA) of Korea. This investigation is intended to outline future and willing to contribute to further use of diagnosis code and the approach of Oriental Medicine to somatic dysfunction. Materials and Methods : By analyzing HIRA data, those diagnosed with M99 codes, a code attributed to somatic dysfunction, were selected for analysis. Patients included were assessed for the relevant general characteristics, and the specific diagnostic criteria. The current usage rates and noteworthy characteristics of diagnostic codes of somatic dysfunctions were assessed. A comparative analysis between clinical departments and subcategories, and a comparative analysis to data of 2014 was conducted. Results : Patients given M99 codes constituted a small minority of all patients diagnosed in 2011 as shown by HIRA data. The codes were more frequently to older patients, females, outpatients, and those who filed for Health Insurance compensation. Medical institutions participating in the diagnosis were mostly primary care facilities, usually specializing in orthopedic(Western medicine sector) and internal medicine (Oriental Medicine sector). The most registered code in 2011 and 2014 was M995. The same trend can be observed in Oriental/Western medicine institutions and Public health center, on the other hand, between them, have some different patterns both 2nd and 3rd. Conclusions : This investigation is that of current usage of diagnostic codes of somatic dysfunction. HIRA insurance claim data was analyzed. Based on the current results, more precise diagnostic standards of somatic dysfunction are warranted. This study will provide a foundation for future Oriental Medicine approach to somatic dysfunctions.

• Journal of Preventive Medicine and Public Health
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• v.33 no.1
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• pp.17-24
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• 2000

Objectives : To propose the referential data to evaluate the health impacts of Vietnam veterans' children whose father were exposed to herbicides in Vietnam War. Methods : Vietnam veterans who visited to Pusan Veteran Hospital for medical care were recruited from April to October, 1998. They were 71 and asked about their own combat history, symptoms and illness, and health status of their 182 children. The informations were collected by direct and phone interview. Exposure estimation was also performed as exposure score depending on year and unit of participation, and personal episodes related to exposure to herbicide in the war. It classified into three groups; lower(<18.0), moderate(18-53), high$(\geq53)$ exposure group. Results : The mean age and the period into the combat of the veterans were 52.8 years and 15.0 months. The mean exposure score was $18.1{\pm}9.9$, and mainly distributed in lower (46.5%) and moderate(52.1%) exposure group. Most(90.1%) of them were diagnosed as sequelae(21 cases) and suspected sequelae(43 cases) of the herbicides by Korean veteran's hospital diagnostic criteria. The major sequelae was peripheral neuropathy 13 cases, chloracne 5 cases, and the major suspected sequelae was hypertension 20 cases, diabetes mellitus 18 cases, liver disease 12 cases, central neuropathy 11 cases, etc. About birth, 42.2% and 16.9% experienced spontaneous abortion and stillbirth, respectively. The mean exposure score was higher in stillbirth experience group(p<0.05). About half of the children(90 cases, 49.5%) hold the abnormal health status: those were skin pigmentation 38 cases, rash 23 cases, congenital anomaly 15 cases, general weakness 12 cases, purpura 8 cases, visual disturbance 8 cases, etc. These health problems had no association with father's exposure level(p>0.05). Conclusions : These results were depend on their own answers, and expectation for compensation did not excluded, therefore, this study may have limitations: inaccuracy of informations due to recall bias and response bias. Nevertheless, through this study, we could image the fundamental aspect for health impacts of Vietnam veterans' children for preparing the national control program and policy. A large scale epidemiologic study with valid exposure assessment on the health impacts of Vietnam veterans' children is recommneded.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.28 no.2
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• pp.100-105
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• 2017

Background and Objectives : Adductor type spasmodic dysphonia (ADSD) is neurogenic disorder and focal laryngeal dystonia, while muscle tension dysphonia (MTD) is caused by functional voice disorder. Both ADSD and MTD may be associated with excessive supraglottic contraction and compensation, resulting in a strained voice quality with spastic voice breaks. The aim of this study was to determine the utility of spectrogram analysis in the differentiation of ADSD from MTD. Materials and Methods : From 2015 through 2017, 17 patients of ADSD and 20 of MTD, underwent acoustic recording and phonatory function studies, were enrolled. Jitter (frequency perturbation), Shimmer (amplitude perturbation) were obtained using MDVP (Multi-dimensional Voice Program) and GRBAS scale was used for perceptual evaluation. The two speech therapist evaluated a wide band (11,250 Hz) spectrogram by blind test using 4 scales (0-3 point) for four spectral findings, abrupt voice breaks, irregular wide spaced vertical striations, well defined formants and high frequency spectral noise. Results : Jitter, Shimmer and GRBAS were not found different between two groups with no significant correlation (p>0.05). Abrupt voice breaks and irregular wide spaced vertical striations of ADSD were significantly higher than those of MTD with strong correlation (p<0.01). High frequency spectral noise of MTD were higher than those of ADSD with strong correlation (p<0.01). Well defined formants were not found different between two groups. Conclusion : The wide band spectrograms provided visual perceptual information can differentiate ADSD from MTD. Spectrogram analysis is a useful diagnostic tool for differentiating ADSD from MTD where perceptual analysis and clinical evaluation alone are insufficient.

• Fire Science and Engineering
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• v.27 no.3
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• pp.30-37
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• 2013

The ultimate purpose of the present study is to secure a effective method for foam liquid discharge when the mixing ratio deviates from the permissible range due to a decrease in the bypass flow rate resulting from a decrease in the cross sectional area of the foam liquid piping ranging from the branching header of one foam proportioner to the branching headers of multiple branching foam fire-extinguishing systems in the region for fire extinguishing and then to the standpipe at the lower part of the storage tank when a fire occurred in a combustible tank. To this end, the cause of mixing ratio variations following changes in the flow rates of existing foam fire extinguishing systems was analyzed, methods for compensation for constant mixing ratios were investigated, and it was proved that metering orifice replacements that could expand the cross sectional area of the stock solution inhaling piping was the most effective way for the improvement of form fire extinguishing systems' mixing ratios through foam proportioner venturi, foam chamber orifice, and metering orifice replacement experiments.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.1
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• pp.38-47
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• 2016

Objectives: The objective of this study was to determine the exposure levels of forklift operators to diesel engine exhaust(DEE) using black carbon(BC), elemental carbon(EC), and nitrogen dioxide($NO_2$) as indicators. Methods: A total of eight forklift operators in six collection companies were assessed over a period of two months from July to September 2015. BC was measured using a real-time monitor and respirable EC samples were analyzed using the NIOSH method 5040. $NO_2$ samples were collected using a passive badge-type sampler. Results: The geometric mean of BC, EC and $NO_2$ were $3.1-19.1{\mu}g/m^3$, $2.1-23.8{\mu}g/m^3$, and 12.5-166.6 ppb at all companies. When forklifts were operating both outside and inside, BC concentrations increased 2.0-5.6 times. The highest increase was observed when forklifts were operating indoors. The increase in BC concentrations varied by company(company A: 2.0 times, B: 3.2 times, C: 5.6 times, D: 2.1 times, E: 5.1 times, F: 2.6 times). The geometric mean of BC, EC, and $NO_2$ for the forklift operators was $9.6{\mu}g/m^3$, $7.9{\mu}g/m^3$, and 48.9 ppb, respectively. The geometric mean of BC, EC, and $NO_2$ for manufacturing workers was $9.3{\mu}g/m^3$, $0.9{\mu}g/m^3$, and 85.2 ppb, respectively. The mean BC and EC exposure levels for the forklift operators were slightly higher than those for manufacturing workers, but $NO_2$ levels for manufacturing workers were higher than those for the forklift operators(p>0.05). Multiple regression analysis revealed that diesel exhaust emissions standard, forklift weight and forklift manufacturer were the most influential factors in determining worker exposure. Conclusions: In the DEE work environment, workers who perform tasks within the workplace as well as inside forklifts as operators are likely to be exposed to a lack of ventilation. Further study of forklift operators' exposure to DEE indicators should be conducted to include a wider range of occupational and environmental situations, such as collection procedures, seasonal situations, types of fuel used, and number of forklifts.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.310-320
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• 2014

Backgrounds: Endotoxin, which found in the outer membrane of the gram-negative bacteria cell wall, makes up almost all of the lipopolysaccharide(LPS). When people are exposed to endotoxin,it can result in diverse health effects such as an airway irritation and inflammation, fever, malaise, bronchitis, allergic asthma, toxic pneumonitis, hypersensitivity lung disease. Cases among the elderly, children or pregnant can occur more frequently than a healthy adult if they are repeatedly exposed to the existing endotoxin. Therefore, we investigated and assessed the environmental characteristics associated with the airborne endotoxin concentration level in six hospital lobbies. Method: Endotoxin from indoor air in six hospital lobbies was measured by an area sampling method and analyzed according to American Society for Testing and Materials International(ASTM international) E2144-01. Total suspended particulate(TSP), carbon dioxide($CO_2$), temperature and humidity were also measured by using direct reading measurements or airborne sampling equipment at the same time. Environmental characteristics were appropriately divided into two or three groups for a statistics analysis. One-way analysis variable(one-way ANOVA) was used to examine a difference of the endotoxin concentration, depending on the environmental characteristics. In addition, only variables with p-value(p<0.25) were eventually designed to the best model by using multiple regression analysis. Results: The correlation analysis result indicated that TSP(p=0.003) and $CO_2$(p<0.0001) levels were significantly associated with endotoxin concentration levels. In contrast, temperature(p<0.068) and humidity(p<0.365) were not associated with endotoxin concentration. Levels of endotoxin concentration were statistically different among the environmental characteristics of Service time(p=0.01), Establishment of hospital(p<0.001), Scale of hospital(p=0.01), Day average people using hospital(p=0.03), Cleaning time of lobby(p=0.05), Season(p<0.001), and Cleaning of ventilation system(p<0.001) according to ANOVA. Finally, the best model(Adjusted R-square=72%) that we designed through a multiple regression test included environmental characteristics related to Service time, Area of lobby, Season, Cleaning of ventilation system, and Temperature. Conclusions: According to this study, our result showed a normal level of endotoxin concentration in the hospital lobbies and found environmental management methods to reduce the level of endotoxin concentration to a minimum. Consequently, this study recognized to be requirement for the management of ventilation systems and an indoor temperature in order to reduce the level of endotoxin concentration in the hospital lobbies.

• 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.