• Proceedings of the KWS Conference
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• 2009.11a
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• pp.97-97
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• 2009

The use of thin plate increases due to the need for light weight in large ship. Thin plate is easily distorted and has residual stress by welding heat. Therefore, the thin plate should be carefully joined to minimize the welding deformation which costs time and money for repair. For one effort to reduce welding deformation, it is very useful to predict welding deformation before welding execution. There are two methods to analyze welding deformation. One is simple linear analysis. The other is nonlinear analysis. The simple linear analysis is elastic analysis using the equivalent load method or inherent strain method from welding experiments. The nonlinear analysis is thermo-elastic analysis which gives consideration to the nonlinearity of material dependent on temperature and time, welding current, voltage, speed, sequence and constraint. In this study, the welding deformation is analyzed by using thermo-elastic method for PCTC(Pure Car and Truck Carrier) which carries cars and trucks. PCTC uses thin plates of 6mm thickness which is susceptible to welding heat. The analysis dimension is 19,200mm(length) * 13,825mm(width) * 376mm(height). MARC and MENTAT are used as pre and post processor and solver. The boundary conditions are based on the real situation in shipyard. The simulations contain convection and gravity. The material of the thin block is mild steel with $235N/mm^2$ yield strength. Its nonlinearity of conductivity, specific heat, Young's modulus and yield strength is applied in simulations. Welding is done in two pass. First pass lasts 2,100 second, then it rests for 900 second, then second pass lasts 2,100 second and then it rests for 20,000 second. The displacement at 0 sec is caused by its own weight. It is maximum 19mm at the free side. The welding line expands, shrinks during welding and finally experiences shrinkage. It results in angular distortion of thin block. Final maximum displacement, 17mm occurs around welding line. The maximum residual stress happens at the welding line, where the stress is above the yield strength. Also, the maximum equivalent plastic strain occurs at the welding line. The plastic strain of first pass is more than that of second pass. The flatness of plate in longitudinal direction is calculated in parallel with the direction of girder and compared with deformation standard of ${\pm}15mm$. Calculated value is within the standard range. The flatness of plate in transverse direction is calculated in perpendicular to the direction of girder and compared with deformation standard of ${\pm}6mm$. It satisfies the standard. Buckle of plate is calculated between each longitudinal and compared with the deformation standard. All buckle value is within the standard range of ${\pm}6mm$.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.97-105
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• 2009

It is expected that logistics standardization have an great effect on industry and national economy due to cost saving and improving efficiency. Therefore all countries of the world make a strenuous effort to take a lead of logistics standardization Despite such efforts of every country, our country remained a lukewarm attitude about logistics standardization. Especially, our country remained a lukewarm attitude about logistics standardization effect quantify. We have to suggest the necessity of standardization and the effect for carrying out logistics standard. So, this study performed literature review and case study for development of effect valuation method. Also, this study developed effect valuation standard for quantifiable standardization effect and drew the effect valuation standard model. First, the measure of preliminary effectiveness was chosen for MOE selection. As a results, vehicle load ratio, delivery cost, keeping space efficiency warehouse automation ratio, etc. were selected. Then, vehicle/truck load ratio, warehouse keeping efficiency, up unloading hour, packaging cost, consistency transportation ratio were chosen for MOE of pallet standardization.

• Fire Science and Engineering
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• v.30 no.1
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• pp.104-110
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• 2016

Positive displacement pumps with high pressure and water capacity are used large fires in various high-rise buildings. This study provides information for a performance approval standard of fire pumps for fire trucks based on centrifugal pump standards enacted in 2012. An experiment was conducted with a positive displacement pump for three levels of performance from the approval standard (V-1, 2, and 3). The efficiency of the pump was included in the reference, which requires the approval of 65% performance, the same as a centrifugal pump. The water pressure is between 1.5 and 2.5 MPa, and the required flow rate was established as at least $0.31m^3/min$ and up to $3.0m^3/min$. A relief valve was added to adjust the shut-off pressure due to the structural characteristics of the positive displacement pump. A strainer was also installed to prevent damage to the inside of the pump due to foreign matter. However, the strainer includes a difference from the positive displacement pump to operate without a vacuum pump and the centrifugal pump. This is due to the additional approval standard portion of the positive displacement pump, which is expected to be selected for more variety of fire-fighting equipment and proactive responses to fire suppression in a high-rise buildings and large fires. In conclusion, this approval standard was enacted in January 2016.

• Journal of the Korean association of regional geographers
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• v.2 no.2
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• pp.113-131
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• 1996

The purpose of this study is to identify the existence, personal characteristics and behavior of market-participants, and function of urban weekly markets in Taegu City through observation, interview and questionnaire survey. There are four weekly periodic markets such as Seongso(Monday), Chilgok(Wednesday), Siji(Thursday), and Chilgok(Friday) which have recently developed near the new apartment areas on the outskirts of Taegu. The major findings of this study can be summarized as follows: These markets originated from the agricultural cooperative's Friday markets, but were substantially established by mobile traders or merchants for the sake of their livelihood. Therefore, the existence of these markets is not explained by Stine's central place perspective but partially explained by Hay's economic locational and Bromley's socio-cultural perspective. Most traders are male, aged 30 to 40 years and have an educational level higher than high school. Most of them are living in Taegu and itinerantly visit more than two markets among the four markets by small truck. And most of them sell agricultural products and other food materials, except some who sell manufactured goods. Most consumers are housewives, aged 20 to 30 years and have an educational level higher than high school. Most of them are living within 1,000m and go there on foot. Most of them visit the markets around 3 to 5 p.m. on every market day. And they mostly buy vegetables, fruits, and fishes. Weekly markets provide employment opportunities for those who want to be merchants, and also contribute to the increase of farmers' income, because some traders(18.8%) are farmers who periodically visit markets to sell agricultural products. On the other hand, they function as a general food materials markets to neighboring residents. From these facts, both traders and consumers want weekly markets sustained. Therefore, these markets need to be protected by institutional assistance in spite of being informal markets.

• Archives of Reconstructive Microsurgery
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• v.16 no.2
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• pp.113-118
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• 2007

Purpose: The purpose of this work was to describe the results of treatment for motor vehiclerelated crushing injuries among children and adolescents under sixteen years in Korea. Materials and Methods: A retrospective analysis was conducted of data from children who were under sixteen year and injured foot by motor vehicles. Cases were documented 1) age at the time of injury, 2) injured site, 3) the area of accident, 4) the kind of vehicle, 5) associated injuries, 6) methods of treatment for soft tissue reconstruction and 7) complications. The relationships between the area of accident and associated injuries, and the kind of vehicle and associated injuries were analyzed using Chi-square test and Fisher exact test. Results: There were 97 children who were 15 year and younger. The mean age was 7.4 years, and 65% were boys. The left foot was more dominant side of injury (57%). Seasonal variation was seen with the number of injuries peaking during the summer (43%, p<0.05). Among the vehicles, 78.3% were the large vehicles (bus, truck or van). The where of accident was more frequent at an alley or less than two lanes of traffic. But, the relationships between the place of accident and associated injury or the kind of vehicles and associated injury were not statistically significant. The associated injury were fracture or dislocation (23 cases, 35.9%), injury of tendon (21 cases, 32.8%). There were amputation or disarticulation of foot in 8 cases (8.2%) and post-traumatic deformities such as flatfoot, hindfoot varus or valus deformities by tendon injury in 7 cases (7.2%). Conclusion: More than 50% of crushing or degloving injuries of child's foot by traffic accidents happened in boys between 5 to 9 years old. The associated injury was unrelated with size of vehicles or accident place at the time of accident. But, even though foot injury happened in an alley or one lane by small vehicles, child who hurt feet by car need thorough investigation about associated injury. If a surgeon keep in mind and treat child to associated injury necessarily, can minimize complication. Microsurgical reconstruction for soft tissue defect was prior to other methods.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.98-106
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• 2011

The deck of steel box girder bridges is composed of deck plate, longitudinal rib, and transverse ribs. The orthotropic steel decks have high possibility to fatigue damage due to numbers of welded connection part, the heavy contact loadings, and the increase of repeated loadings. Generally, the local stress by the repeated loadings of heavy vehicles causes the orthotropic steel deck bridge to fatigue cracks. The increase of traffic volume and heavy vehicle loadings are promoted the possibility of fatigue cracks. Thus, it is important to exactly evaluate the structural behavior of bridge considering the contact loading area of heavy vehicles and real load patterns of heavy trucks which have effects on the bridge. This study estimated the effect of contact area of design loads and real traffic vehicles through the finite element analysis considering the real loading conditions. The finite element analysis carried out 4 cases of loading patterns in the orthotropic steel deck bridge. Also, analysis estimated the influence of contact area of real truck loadings by the existence of diaphragm plate. The result of finite element analysis indicated that single tire loadings of real trucks occurred higher local stress than one of design loadings, and especially the deck plate got the most influence by the single tire loading. It was found that the diaphragm attachment at joint part of longitudinal ribs and transverse ribs had no effects on the improvement of structural performance against fatigue resistance in elastic analysis.

• Journal of Biosystems Engineering
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• v.26 no.4
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• pp.315-322
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• 2001

Agricultural products can be damaged due to the vibration of transporting trailer on the off-road. So, this study was conducted to identify the vibration characteristics of the agricultural products transporting trailer by measuring the vertical acceleration according to positions on the trailer loaded with agricultural products. The results of this study can be summarized as follows: 1. At non-operating state of engine, the larger vertical acceleration was occurred at rear side compared with front side in the case of 4.5Hz of vibration frequency. But, in the case of 53.5Hz of frequency, the maximum vertical acceleration at front side of trailer was higher than value at rear side. So, the maximum acceleration at front side of the trailer was increased with the increase in frequency. 2. At operating state of engine, the maximum vertical acceleration at front side of the trailer was increased with the increase in frequency. 2 At operating state of engine, the maximum vertical acceleration delivered through the hitch from the engine was occurred at front side of the trailer as $3.0\times10^{-3}m/s^2$, in the case of 8.75Hz of frequency. But, in the case of 102.5Hz of high frequency, the maximum vertical acceleration was occurred at rear side of the trailer. 3. When the power tiller loaded with pear of 325kg was travelling on the artificial uneven road of 3cm height, the maximum acceleration was occurred at rear side of the trailer as $4.7\times10^{-3}m/s^2$at 3.75Hz of frequency. But, that was occurred at diagonal of the trailer 43.5Hz and 91.25Hz, which meant that there was rolling and pitching on the trailer. 4. At operating state of engine, the mean acceleration of the trailer delivered through the hitch according to the increase in frequencies was showed the maximum value at range of 40-90Hz. At rear side of traiㅣer, the maximum value was occurred at about 40Hz, and that was reduced according to the increase in frequencies and diminished at about 100Hz. 5. When the power tiller loaded with pear of 32.5kg was travelling on the artificial uneven road of 3cm height, the mean acceleration by the increase in frequencies was showed lower level at rear side than front side of the trailer. This was opposite configuration to the Hinsch’s results tested with air-conditioned truck. This means that the shorter length of the trailer, the more effect of engine vibration is transferred to the front side of trailer.

• Food Science and Preservation
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• v.24 no.7
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• pp.915-922
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• 2017

This study aimed in onion production by evaluating cost and labor efficiencies of onion storage methods using either a ton-bag or a wire-steel pallet. New methods using ton-bag and wire-steel pallets were developed and applied to postharvest tasks, such as harvest packaging, transportation, and storage. The storage parameters evaluated for their effect on the logistics of onion production were: working duration, working hours, and cost expenditure. The longitudinal tensile strength of the ton-bag developed in this study was 16% higher than that of the conventional ton-bag. The wire-steel pallet developed in this study had 10% more storage capacity in a low-temperature storage room, and its truck loading capacity was more than doubled compared to that of the conventional steel pallet. There was no difference in the wasting rate during bulk storage between the newly developed wire-steel pallet and the conventional steel pallet, for 500 kg of onions. However, the bulk storage of 1,000 kg of onions using the wire-steel pallet was not found to be suitable, because the wasting rate of onions stored using the wire-pallet was 3.7% higher than that of onions stored using a conventional steel pallet. The time and the total investing costs for the bulk method decreased by 50.1% and 46.1%, respectively, compared to those for conventional harvest. In the bulk storage using the wire-steel pallet, the total storage cost decreased by 28.8%. Thus, it is estimated that we could have saved 18.3 billion won if the wire-steel pallet method about 30% of the total onion production (1,298,749 M/T) in 2016.

• Fire Science and Engineering
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• v.29 no.2
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• pp.44-53
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• 2015

This study is a survey research to improve the fire-fighting ambulance interior design safer and more efficient to identify the type of structure and functional problems 119 ambulance. When the paramedics and four degrees to over 755 people modify the target report and related literature on the future development of an ambulance for patient safety at the 2007 British National Patients Safety Agency (NPSA) and was used as a complementary tool. General characteristics questionnaire was composed of items for your design improvements for ambulance promote safety and efficiency. The data were collected by distributing a questionnaire e-mail or in person. The collected data were processed using the SPSS 20.0 statistical program, the general characteristics as frequency analysis, percentage, ambulance interior design improvement-related items were analyzed using the chi-square verified. As a result, this research elicited that vans converted fire ambulance cars have a problem with the narrow interior space and truck converted fire ambulance cars should be comfortable to drive in ride quality. In addition, we also found that the improvement of paramedics treatment position and the paramedic's personnel safety belt are required. Based on these results, we propose that a number of improvements are needed in the fire-fighting ambulance car.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.2
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• pp.33-44
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• 2013

Although many studies have been performed for the structural details of orthotropic steel deck, most of them were focused on the trough rib of standard type, but not for orthotropic steel deck with longitudinal rib of open section used at beginning of the deck. In order to investigate the cause of fatigue crack for orthotropic steel deck bridge serviced 31 years with longitudinal rib of open section, in this study, the behavior characteristics of target structural details were analyzed based on measurement data under real traffic condition. Also the typical loading truck passing the target bridges was estimated with the structural analysis detailed, and the stresses and deformation patterns of target structural details were analyzed by performing the detailed structural analysis. Based upon the analysis, retrofitting methods of the fatigue crack were suggested and its validation was examined. From this study, it was clarified that fatigue crack of longitudinal rib with open section were affected with the stress increment by shear deformation in the rib and the occurrence of alternative stress due to moving vehicle. In addition, it was known that it is important to perform fatigue design reflected the local behavior of the structural details.