• Laser Solutions
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• v.14 no.2
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• pp.1-7
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• 2011

The latest trends of vehicle technology development are fuel efficiency improvement, body designs declining air resistance and lightweight of materials. Especially, as lightened weight of materials makes engine efficient so that vehicles keep the best performance, it is the best way to protect the environment and reduce fuel consumption. In this study, we conducted laser welding by using 3-dimension remote scanner that is 5J32 aluminium alloy. Furthermore, conduction experiment that was 3 times repeated for changing factors such as observing angle, laser power and welding speed. we observed exterior and cross section of weled part and tensile strength. When increasing laser power and decreasing laser speed, tensile strength increased. In order to evaluate factors that affect tensile strength qualitatively we conducted ANOVA. We assumed that the factors are observing angle, laser power and welding speed. Then we found that laser power and laser speed affect tensile strength. We conducted evaluation of weldability of aluminium alloy by above ways.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.6
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• pp.61-67
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• 2011

The cooling module needs enough space (or distance) from hood to absorb the energy from any pedestrian collision. Downsized cooling module for pedestrian protection is important to reduce the severity of pedestrian injury. When a vehicle collision happens, the downsized cooling module is required to reduce the risk of injury to the upper legs of adults and the heads of children. In this study, the performance of cooling module to cool the engine was investigated under 25% height reduction. The heat dissipation and pressure drop characteristics have been experimentally studied with the variation of coolant flow rate, air inlet velocity and A/C operation ON/OFF for the downsized cooling module. The results indicated that the cooling performance was about 94% level compared to that of the conventional cooling module. Therefore, we checked that the cooling module had good performance, and expected that the cooling module could meet the same cooling performance as conventional cooling module through optimization of components efficiency.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.11
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• pp.699-704
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• 2011

The compressor's efficiency affects on the fuel consumption of the vehicle because the compressors for car air-conditioning system are operated by engine-driven. Especially, the refrigerant is being changed recently from R134a to substitution refrigerant to protect environment pollution that people concerned about. However, that leads to lower efficiency of the car airconditioning system and worse fuel consumption of the vehicle. Thus, this paper is focused on the methods for improvement of the compressor's efficiency that affects on the fuel consumption of the vehicle by numerical analysis for compressor's performance and the measurement of cylinder volume and pressure when the compressor is being operated.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.38-44
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• 2000

In general liquid rocket nozzles are protected from hot combustion gas by regenerative cooling techniques. But due to the complexity of the cooling system, it causes increase of system cost and frequently source of the system malfunction. Recently, instead of regenerative cooing, ablative material are used to protect combustion chamber wall and nozzle. To determine the nozzle material erosion rate and erosion shape, more than 500 hot fire test were performed by using 100 lb thrust experimental liquid rocket. Test variable were propellant feed sequence, injector, position of igniter and liquid oxygen supply temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.8
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• pp.331-336
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• 2016

This study presents a coolant density calculation device and its corresponding method by using a mass flowmeter and the LabVIEW program. The method can be easily measured with a mixture of coolant and by calculating the percentage of ethylene-glycol without additional investment. The cooling water is very important in a vehicle to protect the engine, and the cooling performance is affected by the mixture concentration and coolant density. The coolant density calculation device measures the mixed concentration in the anti-freeze cooling mixture made from distilled water and ethylene-glycol in real time with the mass flowmeter that is commonly attached to the radiator or heater core. The calculation program for the mixture concentration percentage was developed using the LabVIEW software. The correlation between experimental results and the calculation was conducted for a range of temperature from 40 to $90^{\circ}C$ and by varying the mixture ratio of distilled water and ethylene-glycol. As a result, the anti-freeze coolant concentration in the volume percentage is able to monitor the coolant density in a timely basis by implementing a mixture concentration calculation program without the need for additional equipment investment. The results of the calculation for the mixture concentration level show a maximum 2.7% deviation compared to the experimental results.

• Asia Pacific Journal of Business Review
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• v.3 no.2
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• pp.43-66
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• 2019

Home-based business (HBB) is one of the fastest growing form of business start-ups where the business is conducted from home. In develop economies, the HBB industry is an engine for economic growth that has proven its viability through significant contribution to the national GDP. In view of its importance, the Saudi Ministry of Commerce and Industry encourage local women to start and develop their own HBB as it gives them the flexibility while still contributing to the national economy. Although various initiatives have been taken place, little information is available about Saudi HBB. This study therefore aims to determine the factors that contribute to the growth as well as the challenges of female HBB in Saudi Arabia. The study was based on qualitative approach which adopted an in-depth interview with eleven Saudi females who run HBB. The findings revealed that HBB contributing factors comprised of access to funding, sufficiency of savings and the influence of the intrinsic and extrinsic motivation in starting the business. Meanwhile, the obstacles are government regulations and policies, culture, and home design. The study recommendations include improving banks and service institution policy and procedures to enable HBB to have access to funding and services and to develop legal policies to protect the right of the HBB operator and customers. Finally, the study also suggests future research on managerial factors that can contribute to HBB female success, the stress coping mechanism of HBB and the factors contributing to the difference between HBB in growth strategies.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.108-119
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• 2020

Dynamic pressure sensor used in liquid rocket engine combustor and gas turbine is recess-mounted usually because it should work in high temperature environment. Although recess-mounted method can protect it from combustion gas in high temperature, tube resonance occurs in a tube-cavity system. To reduce it, the infinite tube probe(ITP) was introduced in this study. The ITP model suggested in previous literature was validated with experimental data and frequency response characteristics were analyzed. Guidelines for designing the ITP were suggested as frequency response profiles varied with geometric information and physical properties using this model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.451-457
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• 2020

Format recognition and OCR techniques are widely used as methods for detecting and protecting personal information from electronic documents. However, due to the poor recognition rate of the OCR engine, personal information cannot be detected or false positives commonly occur. It also takes a long time to analyze a large amount of electronic documents. In this paper, we propose a method to improve the speed of image analysis of electronic documents, character recognition rate of the OCR engine, and detection rate of personal information by improving the existing method. The analysis speed was increased using the format recognition method while the analysis speed and character recognition rate of the OCR engine was improved by image correction. An algorithm for analyzing personal information from images was proposed to increase the reconnaissance rate of personal information. Through the experiments, 1755 image format recognition samples were analyzed in an average time of 0.24 seconds, which was 0.5 seconds higher than the conventional PAID system format recognition method, and the image recognition rate was 99%. The proposed method in this paper can be used in various fields such as public, telecommunications, finance, tourism, and security as a system to protect personal information in electronic documents.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.282-287
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• 2016

Recently in order to protect the ocean environment and to reduce energy consumption, shipbuilders have been developing highly economized ships. This research analyzed the possibility of adopting the onshore absorption refrigerator to offshore ships having a cooling system with refrigerant by using the waiste heat of the engine jacket cooling water instead of compression refrigerators. The results showed that R236fa could be a suitable medium for absorbing the heat of the absorber and condenser in an absorption refrigerator. The cooling system using R236fa achieved a high COP of 0.798, which is 15% and 5% higher than an air cooling system with a cooling tower and a water cooling system with a heat exchanger, respectively. The cooling system with R236fa achieved high efficiency with a 25% reduction in flow rate of LiBr solution and only 15.7% flow rate of cooling medium as compared to the water cooling system. The heating of sea water by the engine jacket water flowing out from the generator can prevent the crystallization of LiBr solution due to the low temperature of sea water.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.180-184
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• 2016

Legislative and regulatory actions regarding the exhaust gas from ships are being strengthened by both international organizations and national governments, to protect human health and the environment. Exhaust gas traps are excluded from exhaust gas regulation applications, but, recently, the United States, Britain, and other developed countries have examined a variety of ways to improve the system, including the introduction of electric propulsion systems to prevent air pollution generated by naval ships. This study investigates a large number of smoke problems of naval diesel engines to verify the effect of improving the nozzle characteristics. An exhaust gas emission measurement method to determine the quality of pollutant exhaust gas generated during low-load operation is proposed through the research methodology of the smoke problem. It was confirmed that the emissions value is improved by decreasing the nozzle hole diameter and increasing the injection pressure. At the same time, the flow rate decrease equation and setting up a test memo based on the nozzle diameter confirmed that the fuel consumption, to which the nozzle diameter in the flow path is related, is reduced.