• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.301-306
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• 2016

During the initial stage of propulsion shaft design, the shaft alignment process includes a thorough consideration of lateral vibration to verify the operational safety of the shaft. However, a theoretical method for analyzing forced lateral vibrations has not been clearly established. The methods currently used in classification societies and international standards can only ensure a sufficient margin to avoid the blade-passing frequency resonance speed outside the range of ${\pm}20%$ of the maximum continuous rating (MCR) for the engine. Typically, in shaft alignment analyses, longer center distances between the support bearings promote affirmative results, but the blade order resonance speed can approach the lower limit for lateral vibration. Therefore, this matter requires careful attention by engineers, and a verification of the theoretical analysis by experimental measurements is highly desirable. In this study, both theoretical and experimental analyses were conducted using strain gauges under two draught conditions of vessels used as 50,000-DWT oil/chemical tankers, introduced recently as eco-friendly ships. Based on the analyses, the influence of the lateral vibration on the shafting system and the system's reliability was reviewed.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.5 no.2
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• pp.89-114
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• 2010

In this research is The research on the Entrepreneurship's will according to college students's MBTI personality type and job'2 type through Definition and types of Entrepreneur, rely on the theoretical study of business, MBTI personality type, on the theoretical insights. The relationship between MBTI personality types and to the Entrepreneurship's will models for design verification, and regression analysis, the reliability was conducted. Research Results, Personality types of College students's in the Entrepreneurship's will to significant minus (-) effected. Personality type of I/E of the type of Entrepreneurship's will interest for the (+) of the impact and Attitude for success in business life (+) does not affect the said. Extrovert personality type, with two inbound students compared to students with the type of personality to the Entrepreneurship's will, that Interest for Entrepreneurship's on the side (+) can see the affects.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.867-872
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• 2010

Unused energy derived from sources in nature can be captured and stored for future use, for example, to recharge a battery or power a device; this process of capturing and storing energy is called energy harvesting. Extensive investigations are being carried out in order to use piezoelectricity to harvest the energy generated by body movements or machine vibrations. This paper presents a simple analytical model that describes the output voltage effectiveness of a Piezocomposite Generating Element (PCGE) from vibration and its experimental verification. PCGE is composed of carbon/epoxy, PZT, and glass/epoxy layers. During the manufacturing process, the stacked layers were cured at $177^{\circ}C$ in an autoclave, which created residual stresses in PCGE and altered the piezoelectric properties of the PZT layer. In the experiments, three kinds of lay-up configurations of PCGE were considered to verify the proposed prediction model and to investigate its capability to convert oscillatory mechanical energy into electrical energy. The predicted performance results are in good agreement with observed experimental ones.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.421-426
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• 2017

In this study, we propose a method for predicting the mechanical properties of the printed circuit board (PCB) that has transversely isotropic characteristics. Unlike the isotropic material, there is no specific test standard for acquisition of the transversely isotropic properties. In addition, common material test methods are not readily applicable to that type of laminated thin plate. Utilizing the natural frequency obtained by a modal test and the sizing optimization technique provided in $OptiStruct^{(R)}$, the mechanical properties of a PCB were derived to minimize the difference between test and analysis results. In addition, the validity of the predicted mechanical properties was confirmed by the MAC (Modal Assurance Criteria) value of each of the compared mode shapes. This proposed approach is expected to be extended to the structural analysis for the design verification of the top product that includes a PCB.

• The Research Journal of the Costume Culture
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• v.14 no.2
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• pp.271-285
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• 2006

The purpose of this study was to develop a new basic skirt pattern for 4 lower body types of Plus-sized women. To reduce a time and economic loss about putting it on, This study applied a 3D sample module in the course to develop a basic skirt pattern which is fit, functional and beautiful. A data analysis used the SPSS 11.0 statistics program. To verify the difference, This study used the variance analysis and Duncan's test for the postmortem verification. The result was as follows. To reflect a feature according to an abdomen projection and hip projection, we added the maximum hip circumference to the waist circumference and hip circumference for necessary for a skirt draft item. The front hip circumference sets to the H/4+1cm(ease)+D/4. The back hip circumference set to the H/4+0.5cm(ease)+D/4. The D is the hip circumference in the maximum hip circumference to subtract. The front waist circumference sets to the W/4+0.5cm(ease)+0.5cm(A front and back's difference)+D/4. The back waist circumference sets to the W/4+0.5cm(ease)-0.5cm(A front and back's difference)-D/4. Compare with 4 lower body types of Plus-sized Women, A type 2 and type 4 abdomen projections are bigger. We raised a front waistline of skirt pattern to a 0.3cm upside, and take about 1.3cm down the skirt length from a developed skirt pattern. Consequently, the appearance of a front skirt length was improved with a side skirt length.

• Korean Journal of Agricultural Science
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• v.47 no.1
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• pp.43-58
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• 2020

Mulching plastic is used for the purpose of maintaining soil temperature, moisture, and weed and pest prevention in agriculture. Any remaining plastic after use may contaminate the soil and damage crop growth. To solve this problem, mulching plastic wrappers have been studied and developed, but the actual use rate is quite low due to their poor performance and frequent tearing of the plastic on the field. In this study, we developed a tractor attachable mulching plastic wrapper to minimize the tearing of the mulched plastic. The developed mulching plastic wrapper consists of hydraulic motors and pumps, valves, a microcontroller, and sensors. The collecting speed of the plastic mulch was calculated considering the tractor's travel speed and the radius of the collecting drum. A proportional controller was designed to control the rotating speed of the hydraulic motor as the plastic was wound around the collection drum and the radius increased. The performance of an indoor experiment was quite promising because the difference between the collecting speed predicted by the calculation and the actual collecting speed was 2.71 rpm. Based on a field verification test, the speed difference was max. 14.28 rpm; thus, the, proportional integral derivative (PID) controller needs to be considered to control the drum speed precisely. Another issue was found when the soil covered at the edge of the plastic was hardened or the road surface was uneven, the speed control was unstable, and the plastic was torn. In future research, vibrational plows will be equipped to break-up the harden soil for collecting the plastic smoothly.

• Explosives and Blasting
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• v.26 no.2
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• pp.20-28
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• 2008

In the design stage of a tunnel, the wall convergence is commonly estimated through an elasto-plastic analysis of the tunnel, which has been a topic drawing many researcher's attention so far. Despite its importance, however, the elasto-plastic behavior of a circular tunnel excavated in a generalized Hoek-Brown rockmass is still poorly understood. In this study, a simple munerical method based on Lee & Pietruszczak (2008) for the elasto-plastic analysis of a circular tunnel surrounded by reinforced annulus is proposed. It is assumed that the tunnel is excavated in a strain-softening rockmass obeying the generalized Hoek-Brown failure condition. The commercial code FLAC is used for the verification of the proposed method. The influence of the Hoek-Brown strength parameter a and the thickness of the reinforcement annulus on the elasto-plastic behavior around the tunnel was discussed by conducting some example analyses. The results show that the influence of these two parameters on the distribution of stresses and displacements is substantial.

• Explosives and Blasting
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• v.38 no.2
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• pp.1-12
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• 2020

Digital Image Correlation is a well-established method for displacements, strains and shape measurements of engineering objects. Stereo-camera 3D Digital Image Correlation (3D-DIC) systems have been developed to match the specific requirements for measurements posed by material and mechanical industries. Although DIC method provides the capabilities of scaling a field-of-view(FOV), dimensions of Geotechnical structure objects in many cases are too big to be measured with DIC based on a single camera pair. It can be the most important issue with applying 3D DIC to the measurement of Geotechnical structures. In this paper, We were present stereo vision conditions in a 3D DIC system that can be measured for large FOV(30×20m) and high precisions(z-displacement 0.5mm) of the ground objects with Stereo-camera DIC systems.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.3
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• pp.20-28
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• 2000

The objective of this study is to establish a methodology of bioregional approach for coastal area management as a basis for planning and design. Focusing on the bioregional approach, this study reviewed currently prevailing approaches such as watershed approach and ecological unit approach for planning and management purposes. This research placed its geographical focus on the landward watershed of the Bay of Hampyong located in Chonnam Province, dealing efficiently with shortcomings of existing researches which mainly covered seaward tidal flats without considering outside effects. The main methods of the study are classified into indoor computerized map analysis and field work. For computer analysis, printed maps and digital maps have been analysed, and GIS techniques have been utilized for its synthesis and finalizations. Field work included on-site landscape analysis and verification of a tentative place unit boundary. As a practical step, criteria for classifying bioregion were presented and the selected criteria included : topography & water ways ; roads & administrative boundaries ; habitat types ; and visual enclosure. First, based on the data of topography and water ways, broad classification work was performed and corrections were made based on data drawn out from other criteria. A tentative place unit map was drawn and revised through field visits. This study encompassed an initial but integral part for bioregional approach in landward watershed management of a coastal area. As results of the study, the necessity and efficiency of bioregional approach which considers environmental and cultural components systematically have been presented.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.68-73
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• 2009

One of the traditional optical methods to monitor a tool is a CCD sensor-based vision system which captures an aspect of the tool in real time. In the case using the CCD sensor, specific lens-modules are necessary to monitor the tool with higher resolution than its pixel size, and a microprocessor is required to attain desired data from captured images. Thus theses additional devices make the entire measurement system complex. Another method is to use a pair of an optical source and a detector per measuring axis. Since the method is based on the intensity modulation, the structure of the measurement system is simper than the CCD sensor-based vision system. However, in the case measuring the three dimensional position of the tool, it is difficult to apply to micro machine-tools because there may not be space to integrate three pairs of an optical source and a detector. In this paper, in order to develop a tool-origin measurement system which is employed in micro machine-tools, the improved method to measure a tool origin in x, y and z axes is introduced. The method is based on the intensity modulation and employs one pair of an optical source radiating divergent beams and a quadrant photodiode to detect a three dimensional position of the tool. This paper presents the measurement models of the proposed tool-origin sensor. The models were verified experimentally The verification results show that the proposed method is possible and the induced models are available for design.