• Journal of the Korean BIBLIA Society for library and Information Science
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• v.25 no.4
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• pp.129-146
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• 2014

This study aims to present the effects that a bibliotherapy program based on picture books and paper craft art activities had on middle school students' stress recognition and the changes in their reactions. To this end, we adopted an experimental research design model with pre/post-test measurements of stress recognition and reactions using first grade middle school students with emotional difficulties. The results show that a bibliotherapy program based on picture books and paper craft art activities does have significant effects on the stress recognition and reactions of middle school students. The 5 of 5 sub-domains of the stress recognition had significant difference. The sub-domains are: family environment, friends, study, teacher/school. The 6 of 7 sub-domains of the stress reactions except fatigue had significant difference. The sub-domains are: tention, frustration, anger, depression, somatization, aggression.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.251-257
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• 2011

When designing a ship, ergonomic considerations are crucial when minimizing a navigator's fatigue due to the burden of work, and to appropriately operate the navigational equipment for each given situation by helping the operator to understand the surroundings as well as the physical functions of the ship. However, insufficient consideration of ergonomic elements in the actual design of ship Bridges is lowering the performance of safe navigation and allows for the possibility of operation or readout errors. Consequently, these errors lead to an increase in maritime accidents. Therefore, this study conducted a usability evaluation on the importance of and the usage frequency of navigational equipment, their influence on actual navigation, and the possibility of error upon operation or readout between training ship officers, to derive an optimized layout that includes the consideration of ergonomic factors for on-Bridge navigational equipment, which are currently arranged differently according to their type or size. The optimized layout of on-Bridge navigational equipment was carried out based on the evaluation results, using the Lingo program. Through the process of optimization, revised layouts of on-Bridge navigational equipments(control and display device) were suggested, considering emergency situations(ship collision, stranding, fire and explosion, sinking, etc.) during navigation.

• Journal of the Ergonomics Society of Korea
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• v.32 no.4
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• pp.333-340
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• 2013

Objective: The aim of this study is to provide a current knowledge of the multiple issues regarding motion effects on crew performance. Background: The motions of the ship may create motion sickness, nausea and vomit. Also, these motions also disturb the balance of crew members, increase the energy expenditure of crew for shipboard work, and result in increased levels of injury and fatigue. However, the motion effects of the ship on crew performance has not been thoroughly investigated. Method: Participants(N=10) were engaged in an experiment in 2 experimental environments(training ship and ship handling simulator) and 2 navigational conditions(day and night). The COP(Center of Pressure) data were recorded as an objective measure of postural balance control and the SSQ(Simulator Sickness Questionnaire) was used as a subjective measure of sickness. Results: The results showed that COP has a no significant difference based on experimental environments, but significant effect on SSQ. Conclusion: During the virtual simulator navigation, subjects showed significant SSQ level changes, which included decreased SSQ data. But, there is no significant difference of COP between training ship and ship handling simulator. Application: The results of this study could be applied to the next generation of ship design to decrease effect of motion at sea and to increase performance of ship crew.

• Journal of Korean Academy of Nursing
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• v.16 no.2
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• pp.13-28
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• 1986

The main purpose of th study was to evaluate he validity of Korean Pain Measurement Tool composed of pain terms. The specific purposes of this study were 1. to examine whether pain intensities of pain terms are congruent with those classified in three previous studies. 2. to evaluate the relative intensity of each term by panel of judges. 3. to explore the difference of ranks of pain terms according to the sex, education, and ages. One hundred and sixty normal individuals were selected by 2$\times$2$\times$4 sampling design. Sex (male, female), education (high school, college), and age (20s, 30s, 40s, 50s) were matched. Each individual was asked to rate the ranks of 3~8 pain terms in each subclass. The data measured by ordinal scale were transformed to the interval scale to compare with the pain intensities gained from the previous study. The pain ranks different from previous results were finally rearranged or cancelled through the consultation of 4 panel of judges and sunmed up to 91 pain terms in the scale. As a result, the ranks of pain terms within each of eleven subclasses among the twenty subclasses completely were congruent with the Previous pain ranks, while the ranks of nine subclasses were different from the previous pain ranks. In addition, there was significant relation between sex and pain ranks in skin punctuate pressure pain and cavity pressure. (sp : $\chi$$^2$=5.18 ø=0.26； cp : $\chi$$^2$=5.83 ø=0.24) In conclusion, seven terms from subclasses of inflammatory repeated pain, traction pressure pain, fatigue-related pain, fear-related pain, dull pain, and pulsation. related pain were cancelled. The ranks of four terms in subclasses of incisive Pressure pain and constrictive pressure pain were tentatively rearranged. Ranks of two terms in the tract pain were left as shown in the third study. As a result, six terms must be studied repeatedly for obtaining exact scores from ratio scale.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.3
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• pp.342-350
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• 2003

Statement of problem. Titanium-Nickel alloy might be used in various prosthetic restorations since it has a unique property such as super-elasticity and high fatigue resistance. However, little is known about the casting ability of this alloy. Purpose. This in vitro study compared the casting accuracy and the porosity made with different investments and various sprue designs to ascertain what casting condition would be better for the fabrication of Ti-Ni cast restorations. Material and methods. A total of 70 Ti-Ni alloy crowns were made and divided into 7 groups of 10 copings on a metal master die. For measuring the effect of the sprue numbers, two groups with one and two 8-gauge sprues were compared. Moreover, the results of the conventional sprue and the double thickness sprues were compared. Three investments were used; carbon free phosphate bonded investment, titanium investment and gypsum bonded investment. The cast restorations were evaluated at 48 points on the entire circumferential margin with a stereomicroscope measuring in micrometers. Each crown was radiographically examined for casting defects and porosity. Data on casting accuracy were analyzed using two-way and Post hoc Scheffe's comparison to determine whether significant differences existed at the 95% confidence level. Student-Newman-Keuls test were performed to identify significant differences in the number of voids. Results. The double sprueing group and double thickness group had significantly less marginal discrepancy than the single sprueing group (P<.05 and P<.01, respectively). The castings with phosphate bonded investment showed the least marginal discrepancy and the smoothest surface. The castings invested in the gypsum bonded investment had the greatest gaps in margin and the largest failure rate. The double sprueing group and phosphate bonded investment group had significantly smaller void numbers and smaller void size than the other groups. Conclusion. Within the limitations of this in vitro study, the casting accuracy of the groups using thicker, double sprue design and the phosphate bonded investment was significantly superior. Moreover, void number and size were less than other groups.

• Journal of Ocean Engineering and Technology
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• v.26 no.2
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• pp.48-57
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• 2012

This paper deals with numerical analyses in the context of estimations of hydrodynamic motions and dynamic loads for a floating type offshore platform using some exclusive simulation code such as code for the simulation of a floating type of offshore crane based on multi-body dynamics, along with the commercial code AQWA. Verifications of numerical models are carried out by comparing the RAO results from the simulation code. In the verification analyses, hydrodynamic motions are examined in the frequency domain for the floating type offshore platform according to the mooring lines. Both the hydrodynamic motions and dynamic loads are estimated for floating type offshore platforms equipped with the catenary type and taut mooring lines. A review and comparison are carried out for the numerically estimated results. The structural safety of the connection parts in an offshore structure such as a floating type offshore platform is one of the most important design criteria in view of fatigue life. The dynamic loads in the connecting area between a floating type offshore platform and its mooring lines are estimated in detail according to variations in the mechanical properties of the mooring lines. The dynamic tension load on the mooring lines is also estimated.

• Journal of Ocean Engineering and Technology
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• v.32 no.5
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• pp.297-309
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• 2018

After an accident involving mooring link failures in an offloading buoy, verification of the fatigue safety in terms of the out-of-plane bending (OPB) and in-plane bending (IPB) moments has become a key engineering item in the design of various floating offshore units. The mooring links for an 8 MW floating offshore wind turbine were selected for this study. To identify the OPB stiffness (OPB moment versus interlink angle), a numerical simulation model, called the 3-link model, is usually composed of three successive chain links closest to the fairlead or chain hawse. This paper introduces two numerical simulation techniques for the 3-link analyses. The conventional and advanced approaches are both based on the prescribed rotation approach (PRA) and direct tension approach (DTA). Comparisons of the nominal stress distributions, OPB stiffnesses, hotspot stress curves, and stress concentration curves are presented. The multiple link analyses used to identify the tension angle versus interlink angle require the OPB stiffness data from the 3-link analyses. A convergence study was conducted to determine the minimum number of links for a multi-link analysis. It was proven that 10 links were sufficient for the multi-link analysis. The tension angle versus interlink angle relations are presented based on multi-link analyses with 10 links. It was found that the subsequent results varied significantly according to the 3-link analysis techniques.

• Transactions of the KSME C: Technology and Education
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• v.5 no.2
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• pp.115-126
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• 2017

This paper proposes an accelerated life evaluation of drive shaft for the power train parts of special purpose vehicle. It is necessary the real load data of usage level driving load condition for life evaluation of power train parts, but we can't get the load spectrum data for evaluation in many case of special purpose vehicle. So, in this paper, the road load spectrum data for evaluation is created by modeling and simulation based on vehicle data and special road condition. The inverse power model is used for accelerated life test. The equivalent torque of load spectrum is achieved using the Miner's Rule. This paper also proposes the calibrated acceleration life test method for drive shaft. The fatigue test is performed through three stress levels. The lifetime at normal stress level is predicted by extrapolation, and is verified through comparison of experimental results and load spectrum data.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.88-94
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• 2013

The purpose of this study is to find out the difference of foot pressure according to the firefighter's work postures for providing the basic information to prevent Musculoskeletal disorders. This study was conducted by 9 male firefighters. Work postures were selected for rescuee handling, fire hose and hydraulic rescue equipment work postures. These were divided into 3 position, "High", "Middle" and the postures of taking out and letting down hydraulic rescue equipment were analyzed as starting point and end point respectively. Foot Pressure was used to analyze contact area, peak pressure, and maximum force in terms of work postures, and compared between fire hose and hydraulic rescue equipment work postures. The results of foot pressure are as follows. According to the results of rescuee handling work postures, one person handling posture showed wide contact area and foot pressure showed the highest at right foot. Accoridng to the (High), (Middle), (Low) postures of fire hose, the results didn't show the difference among the contact area, peak pressure and maximum force. As the results of hydraulic rescue equipment work postures, (Low) postures showed the highest in terms of the right foot of contact area, peak pressure and maximum force and (High) postures showed the highest in left foot. The increase of foot pressure lead to be inconvenience of low extremity and muscle fatigue for maintaining postural control cause pain. Thus, it is necessary to design insole-equipped working shoe for reduce the impulse and effect of foot during the rescuee handling work which standing out as foot pressure.

• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.449-455
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• 2010

Implantable middle ear hearing devices(IMEHDs) have being actively studied to overcome the problems of conventional hearing aids. Vibration transducer, an output devices of IMEHDs, is attached on the ossicular chain and transmits mechanical vibration to cochlea. This approach allows us to hear more clear sound because mechanical vibration is effective to transfer high frequency acoustics, but occurs some problems such as fatigue accumulation to ossicular chian and reduction of vibration displacement caused by mass loading effect. Recently, many studies for the round window stimulation are announced, because it does not cause such problems. It have been studied by older transducers designed for attaching on ossicular chain. In this paper, we proposed a new electromagnetic transducer which consists of two magnets, three coils and a vibration membrane. The magnet assembly, magnet coupled in opposite direction, were placed in the center of three coils, and the optimum length of each coil generating maximum vibrational force was calculated by finite element analysis(FEA). The transducer was implemented as the calculated length of each coil, and measured vibration displacement. From the results, it is verified the vibration displacement can be improved by optimizing the length of coils.