• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.243-251
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• 2001

The effects of various operating parameters(agitation speed, impeller type, antiform agents, impeller spacing etc.) on air-liquid mass transfer was characterized by volumetric mass transfer coefficient($k_La$). Also, the dual-impeller agitated systems are compared with single-impeller agitated systems with a special focus on its applications for bioreactors, $k_La$ was take over a range of 200~450 rpm of agitation speed, and 0.5~2.5 vvm of air flow rates, for four single impeller and impeller combinations consisting of four impeller types, namely rushton, pitched blade, scaba, intermig were tested. The rushton impeller showed the best $k_La$ as compared with other single impellers. The dual impeller system are found to be superior as compared to single impeller in all aspects, The best combination of the dual impeller was a intermig of axial flow type as an upper impeller and a rushton of radial flow type as a lower part. Also, the control of the DO level with the variation of agitation speed was more efficient than that with an increase in air flow rate. The addition of antiform dropped the $k_La$ very large up to 1g/L regardless the type. PPG was less effect on $k_La$ than other antiforms. The impeller spacing and presence of solute are found very effective on $k_La$. When the $NaNO_3$is presented as solute, the $k_La$ increased approximately 50% then control.

• Journal of Forest and Environmental Science
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• v.35 no.2
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• pp.78-89
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• 2019

Coastal plantation is one of the key natural defence against the tidal surge induced tropical cyclones. In Bangladesh, a total of 81 km long coastal belt was established from Potenga to Muhuri in Chittagong. This study explores the wind protection efficiency of the coastal plantations at 28 observation points along the 81 km long Potenga-Muhuri irrigation project of Chittagong coastal belt. We found that wind protection efficiency was lowest (1.40% and 7.00%) at $1^{st}$ observation point of outside the embankment (OE) and inside of the embankment (IE) than Sea Shore (SS), respectively. On the other hand, the highest (82.89% and 95.72%) wind protection efficiency was observed at $22^{th}$ observation for Outside of the Embankment (OE) and Inside of the Embankment (IE) than Sea Shore (SS), respectively. This study also highlighted on species specific wind protection efficiency. The result revealed that 6-year old Casuarina, 6-year old mixed plantation and 10-year old Sonneretia apetala with the width of 20.12 m, 30.48 m, and 15.24 m can reduce wind speed up to 30 H, 30 H and 25 H at windward side, respectively. Analysis also showed that percentage of wind reduction was significantly higher at plantation coast than barren, and ship breaking yard coast. The findings of this study have great potentiality to contribute substantially to take more coastal embankment afforestation programs by the Government of Bangladesh and to choose the more wind resistant plant species throughout the coastal areas of the country.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.139-145
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• 2001

Behavior of Matsucoccus thunbergianae Miller and Park males immediately after emergence from their cocooning site, and meteorological factors affecting the responsiveness of the flying males to synthetic pheromone were studied. On Pinus thunbergii saplings, newly emerged males walked around to locate females. The males lanuched themselves into flight after up to three times of copulation. Without the presence of females, the males took off within five minutes whereas when the females were placed nearby but copulation was artifically prohibited the males did not take off. In a wind tunnel, the presence of female pheromone discouraged male take off. More males were flying in sunny area than in shade, but light intensity had no effect on the responsiveness of males toward the pheromone source. Wind speed was the main meteorological factor that affected the male responsiveness. Most males, after hitting the substrate near pheromone source with various posture, stood on their feet and approached the source.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1079-1082
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• 2005

This paper deals with the algorithm development that inspects defects such as Lens Focus, Focus check, Black Defect, Dark Defect, Dim Defect, Color Defect, and Line Defect, Angle Defect, IrisAgc Defect caused by the process of 2M Class Compact Camera Module (CCM). Domestic market was majorly comprised of VGA(0.3 million pixel) market. But in the middle of year 2004, camera phone with Mega Pixel has appeared, and it is estimated that the camera phone with Mega Pixel will take up to 28% of total phone sales if it is released in the end of year 2004. Since the inspection of finished products is done manually, it is major obstacle in production increment In this paper, to solve these problems, we developed the imaging processing algorithm to inspect the defects in captured image of assembled CCM. The performances of the developed inspection system and we can recognize various types of defect of CCM modules with good accuracy and high speed

• Journal of the Korean Institute of Navigation
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• v.24 no.3
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• pp.167-176
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• 2000

The -advent of electronic navigation equipment and trustworthy computer which provides people with convenience made the management system by one-man bridge operation or the least people who are needed possible through the integration of communication network with various navigation equipment and related institution. One of the most needed ultra-modem navigation device for a mate, ECDIS is a core equipment for navigation in ENS that notifies peril to mate as well as supervises all tasks in hydrographical chart, voyage planning, course monitoring and voyage recording. We should make coast and ocean voyage planning first, for the secure navigation which is considering the course circumstances and next, for the reduction of voyage dates in economical aspect. There needs a thoughtful consideration about the feature of the ship itself and the course with weather condition in taking up the course and also we have to take into accounts about appropriate distance between ships. Considering the essential conditions of ECDIS the indispensable device in the future, it was developed the basic principle for voyage planning algorithm for officer and programmed to real implementation available. In this paper including most of the requirements in ECDIS performance standard I mentioned about such a basic and a core Principle with real application by using the Visual C++ programming language. The voyage plan includes the function that indicate and modifies all the way points in the course from department port to arrival port with erasing the wrong way points. Also, it provides in a document form that shows ETA at glance in average speed sailing.

• The KIPS Transactions:PartD
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• v.12D no.3 s.99
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• pp.355-364
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• 2005

Previous researches on subsequence matching have been focused on how to make indexes in order to speed up the matching time, and do not take into account the effectiveness issues of subsequence matching methods. This paper considers the effectiveness of subsequence matching methods and proposes two metrics for effectiveness evaluations of subsequence matching algorithms. We have applied the proposed metrics to Korean stock data and five known matching algorithms. The analysis on the empirical data shows that two methods (i.e., the method supporting normalization, and the method supporting scaling and shifting) outperform the others in terms of the effectiveness of subsequence matching.

• Journal of the Korean Applied Science and Technology
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• v.28 no.3
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• pp.306-312
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• 2011

In this study, we are crystallized to the low density polyethylene (LDPE) micro-particles in $n$-dodecanol solution by thermally induced phase separation(TIPS) method. The Low density polyethylene micro-particles is used in a wide variety of polymer coatings and industrial application. The utility of that for a particular application depends on a number of factors such as the particle size and distribution, and chemical composition of the materials. However, there are still needs for new methods of preparation which will provide the structure with unique sizes. The widely used processes for micro-size particles are crystallization method and thermally induced phase separation. TIPS process based on the phase separation mechanism was performed for the LDPE system which undergoes liquid-solid phase separation. Effects of various operating parameters were examined on the structure variation of the particles. Professionality, take-up speed and crystallization rate depended on temperature and concentration of polymer in solution.

• Polymer(Korea)
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• v.24 no.1
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• pp.113-123
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• 2000

Poly(p-hydroxybenzoate) (PHB)/poly(ethylene terephthalate) (PET) 8/2 thermotropic liquid crystalline copolyester, poly(ethylene 2,6-naphthalate) (PEN) and PET were mechanically blended to obtain the pseudo liquid crystalline (LC) phase of ternary blends. The torque values of blends with increasing PHB content were abruptly decreased above 40 wt% of PHB content, because the melt viscosity of ternary blends decreased. Tensile strength and initial modulus of blends containing above 30 wt% PHB were improved with increasing PHB content. Tensile strength and modulus of fiber were increased with PHB contents and take-up speed. Degree of transesterification and randomness of blends were increased with blending time. The blend of 40 wt% PHB was shown pseudo LC phase in the polarized optical photographs. Crystallinity of PHB/PEN/PET ternary blend were increased with PHB content.

• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.560-564
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• 2013

${\small{D}}$-Ribose is a value-added five-carbon sugar used for riboflavin production. To investigate the effects of oxygen supply and mixed sugar concentration on microbial production of ${\small{D}}$-ribose, a transketolase-deficient Bacillus subtilis SPK1 was cultured batch-wise using xylose and glucose. A change of agitation speed from 300 rpm to 600 rpm at 1 vvm of air supply increased both the xylose consumption rate and ${\small{D}}$-ribose production rate. Because the sum of the specific consumption rates for xylose and glucose was similar at all agitation speeds, metabolic preferences between xylose and glucose might depend on oxygen supply. Although B. subtilis SPK1 can take up xylose and glucose by the active transport mechanism, a high initial concentration of xylose and glucose was not beneficial for high ${\small{D}}$-ribose production.

• ETRI Journal
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• v.28 no.3
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• pp.320-328
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• 2006

Using biometrics to verify a person's identity has several advantages over the present practice of personal identification numbers (PINs) and passwords. To gain maximum security in a verification system using biometrics, the computation of the verification as well as the storing of the biometric pattern has to take place in a smart card. However, there is an open issue of integrating biometrics into a smart card because of its limited resources (processing power and memory space). In this paper, we propose a speaker verification algorithm using a support vector machine (SVM) with a very few features, and implemented it on a 32-bit smart card. The proposed algorithm can reduce the required memory space by a factor of more than 100 and can be executed in real-time. Also, we propose a hardware design for the algorithm on a field-programmable gate array (FPGA)-based platform. Based on the experimental results, our SVM solution can provide superior performance over typical speaker verification solutions. Furthermore, our FPGA-based solution can achieve a speed-up of 50 times over a software-based solution.