• Bulletin of the Society of Naval Architects of Korea
• /
• v.24 no.1
• /
• pp.35-41
• /
• 1987

An approximate method for calculating added resistance due to regular wave reflection has been established. In order to confirm the applicability of this method, an experimental work was carried out using a Series 60 model with oscillations in the 6-degrees of freedom restricted. Particular attention was paid to the case of the shorter wave length range where the effect of wave reflection is dominant compared to the effects of the ship's motions($\lambda/H=10.6-101.0,\;\lambda/L=0.23-1.18,\;F_n=0.10-0.25$). When comparing the measured and the computed resistance due to wave reflection in a head sea, good agreement is shown. This paper is based on research done by the Author as a member of the Ship Performance Group in the Department of Naval Architecture and Shipbuilding of the University of Newcastle-upon-Tyne in England, under the supervision of Dr. R.L. Townsin.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.181-181
• /
• 2013

Recently, nanostructure and the molecular orientation of organic thin films have been largely paid attention due to its importance in organic electronics such as organic thin film transistors (OTFTs), organic light emitting diodes (OLEDs), and organic photovoltaics (OPVs). Among various methods, the diffraction and scattering techniques based on synchrotron x-rays have shown powerful results in organic thin film systems. In this work, we introduce the in-situ annealing system installed at PLS-II (Pohang Light Source II) for organic thin films by simultaneously conducting various x-ray scattering measurements of x-ray reflectivity, conventional x-ray scattering, grazing incidence wide angle x-ray scattering (GI-WAXS) and so on. Using the in-situ measurement, we could obtain real time variation of nanostructure as well as molecular orientation during thermal annealing in metal-phthalocyanine thin films. The variation of surface and interface also could be simultaneously investigated by the x-ray reflectivity measurement.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.22 no.50
• /
• pp.65-73
• /
• 1999

Most psychophysical studies in manual material handling (MMH) have paid more attention to two-handed MMH activities than to one-handed MMH activities. Also, studies are involved only with single MMH activities - lifting, lowering, carrying, holding, pushing or pulling. Very few studies are reported on the determination of workers' capacities for combinations of one-handed MMH activities (lifting a box, then carrying the box, and lowering the box). The objective of this study was to find the psychophysical and physiological responses of human subjects from a simulated industrial task involving one-handed and two-handed combined tasks. The capacities that were determined as the maximum acceptable weight workloads for 1 hr work period for one-handed and two-handed combined tasks - lifting a box from floor to knuckle height, carrying the box for 4.3 m, and lowering the box from knuckle to floor height - were determined psychophysically under three frequencies: six handlings per minute, one handling per minute and one handling per five minutes. In addition to maximum acceptable weight, heart rate and RPE values on wholebody, back, and arm were also measured as responses.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.228-233
• /
• 2004

The length of city gas pipeline is increasing with expansion of natural gas transmission rapidly. A lot of the expense was paid for repair and maintenance with increasing of pipeline length and the cost of repair and maintenance by the corrosion was the highest. It is necessary to evaluate integrity in case of thickness reduction by corrosion. There are a lot of assessment criteria for corrosion defect in foreign countries but they are not suitable for application in the country directly. In this work, we performed the burst test and the finite element analysis for city gas pipeline, KS D3507 and KS D3631 for city gas transmission, and developed the assessment method of corrosion defect, which is suitable for domestic condition.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.05a
• /
• pp.235-239
• /
• 1999

This thesis is concerned with the development of useful engineering techniques to detect and analyze nonlinearities in mechanical systems. The methods developed are based on the concepts of higher order spectra, in particular the bispectrum. The study of higher order statistics has been dominated by work on the bispectrum. The bispectrum can be viewed as a decomposition of the third moment(skewness) of a signal over frequency and as such is blind to symmetric nonlinearities. Initially auto higher order spectra are studied in detail with particular attention being paid to normalization method. Traditional method based on the bicoherence are studied. Under certain conditions, notably narrow band signals, the above normalization method is shown to fail and so a new technique based on prewhitening the signal in the time domain is developed.

• Journal of the Ergonomics Society of Korea
• /
• v.32 no.4
• /
• pp.397-403
• /
• 2013

Objective: This article aims to report the results of ergonomic evaluation of some university laboratories. Background: Laboratory researchers are at risk for musculoskeletal injuries during routine laboratory procedures. However, little attention has paid to the working conditions of laboratory researchers, especially in Korea. Method: A checklist and questionnaire was developed and used to analyze the work conditions of 27 laboratories of chemistry, biology and pharmacy. Results: It was found that glove box, clean bench, and computer workstation are better than microscopy, and fume hood tasks, from ergonomic point of view. Conclusion: No domestic guideline is available for ergonomic intervention of laboratories. Further attention and studies are anticipated to improve the working conditions of laboratories.

• Journal of Families and Better Life
• /
• v.15 no.4
• /
• pp.369-386
• /
• 1997

The major purpose of this study is to investigate the urban husbands' participation in household labor and to predict the amount of their participation in it. The major findings of this study are as follows; 1. Husbands participate in household labor(i.e. the housework and the child care)on the average for 114 minutes a weekday and for 240 minutes a holiday. They participate most in the child care among all the household tasks. The employed wives' husbands participate more in the housework than nonemployed wives' husbands. 2. Husbands' paid work time is the storngest predictor of their participation in household labor on weekdays but the age of the youngest child is the strongest one on holidays to both employed wives' and nonemployed wives' husbands. The implication of these findings for husbands' participation in household labor and future research were discussed.

• Journal of the Korean Society of Safety
• /
• v.16 no.2
• /
• pp.117-120
• /
• 2001

Low back pain has been known as the most frequent musuculoskeletal disorders in modern industrial society and cost by low back pain is increasing mon and more. The asymmetric lifting has been identified as a major risk factor of low back pain. In this study, the muscle activity and muscle exertion level during asymmetric load handling (without trunk flexion) was estimated. The results of normalized MVC measurement were decreased about 16％, 24％, 34％ respectively as the asymmetric angle was $30^{\circ}$, $60^{\circ}$, $90^{\circ}$. From the results of EMG measurement contralateral muscles were more active than ipsilateral muscles. RMSEMG values of right erector spinae muscles were decreased as the work posture went to 90$^{\circ}$ and those of left erector spinae muscles were increased until the asymmetric angle was 40$^{\circ}$ but decreased continually over 40$^{\circ}$. And for seven of subjects, activities of left and right latissimus dorsi muscles were maintained constantly, while for remainer, those were irregular.

• Journal of the Korean Society of Safety
• /
• v.10 no.2
• /
• pp.113-119
• /
• 1995

Many studies have been done to determine the magnitudes of force a man can exert on the objects. However, very little attention has been paid to those In postures on slopes. This paper was aimed to evalute how human work postures would affect the push/pull force and to grasp the relationships between the rectified EMG(REMG) measured at the trunk muscles and force exerted on upward slopes. Two subjects participated in the experiment. The results showed no lineal relationship between the REMG and exerted force at handle. But as the slope and handle height increased, exerted force and muscular stress on erector spinae or rectus abdominis were generally increased. It was notified that since ANOVA did not detect any statistical significance in REMG variation due to dominant muscles, careful application and interpretation of the REMG should be required in analyzing maximal force exertions.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.6
• /
• pp.1673-1681
• /
• 2007

The u-Learning just begins to emerge as the next-generation knowledge-based business. Since it has a great potential to become a high value-added industry, there is much attention paid in this field. In this work, we first summarized the concept of the u-Learning where the architecture of various u-learning areas has been identified. Then we investigated the current status and problems of the u-Learning industry. Through the SWOT analysis, we have extracted the political strategies that will be essential for the rapid industrialization of u-Learning which will, in turn, contribute much to enhance the competitiveness of national economy.