• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.2
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• pp.52-59
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• 2003

Cam mechanism is a machine part frequently used in machinery. Specially, conjugate cam mechanism is very suitable for the high speed working and the heavy power translation. Then a conjugate cam mechanism need high precision for the relations between cam profiles and follower rollers. So, its design and manufacturing are very difficult. Thus, this study is a branch of exclusive CAM systems for design and NC machining of conjugate earn mechanism based on a master plate earn profile in order to exchange an old plate cam mechanism to a new conjugate earn mechanism. For the design of the other cam profile by using a master cam profile, some calculation processes were used by vector summation methods, from master cam profile data to the center data of master follower, from the center data of master follower to the center data of the other follower considered in link mechanism, and offsetting in the center direction of base circle of the other cam from the center data of the other follower. Finally, a sample conjugate cam was selected and machined m order to prove the contents of this study.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.7
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• pp.55-62
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• 2006

This thesis describes collision avoidance using fuzzy logic based on "Right of way" rules of ICAO and FAA and pilot's experiences for Unmanned Aerial Vehicle(UAV). To apply the rules, we designed fuzzy logic based collision avoidance system. And we also designed decision logic for enable condition of collision avoidance system. Decision logic have three kinds of core key, i.e. Relative Range, Time of CPA(Closest Point of Approach) and Distance at CPA. Application of decision logic made a possible to avoid NMAC(Near Mid-Air Collision) and it has been verified through several simulations. To conclude, we proposed the method to carry out "See and Avoid" ability on UAVs, which is capability to mingle with manned aircraft in civil airspace.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.182-189
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• 2012

This study suggests a dynamic design process for deciding properly design parameters of a mass-spring type Wave Energy Converter (WEC) to achieve sufficient energy conversion from wave to power generator. The WEC mechanism, in this research, consists of a rigid sprung body, a platform, suspension springs and dampers. The rigid sprung body is supported on the platform via springs and dampers and vibrates translationally in the heave direction under wave excitation. At last the resulting heave motion of the sprung body is transmitted to rotating motion of the electric generator by rack and pinion, and transmission gears. For the purpose of vibration analysis, the WEC mechanism has been simply modelled as a mass-spring-damper system under harmonic base excitation. Its maximum displacement transmissibility and steady state response can be determined by using elementary vibration theory if the harmonic ocean wave data were provided. With the vibration analysis results, the suggested dynamic design process of WEC can determine all the design parameters of the WEC mechanism, such as sprung body mass, suspension spring constant, and damping coefficient that can give sufficient relative displacement transmissibility and the associated inertia moment to drive the electric generator and transmission gears.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.152-159
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• 2003

This study was conducted to analyze the water consumption in closed transplants production system (CTPS) for the production of quality transplants and to investigate the effect of relative humidity on the water balance in CTPS. Potato (Solanum tuberosum L. cv. Dejima) plug seedlings were grown for 15 days at air temperature of 20$^{\circ}C$, relative humidity of 70%, photoperiod of 16/8 h, and photosynthetic photon flux (PPF) of 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-l}$ following rooting for 5 days in CTPS. Amount of humidified, dehumidified, irrigated and evapotranspirated water were 67.9 kg${\cdot}m^{-2},\;196.9{\cdot}m^{-2},\;44.3\;kg{\cdot}m^{-2},\;33.5\;kg{\cdot}m^{-2}$, respectively. Water content of media and plants were 1.2 kg${\cdot}m^{-2},\;6.9\;kg{\cdot}m^{-2}$, respectively. Three relative humidity levels of 60, 70, and 80% were provided to analyze the effect of humidity on the water balance in CTPS. Amount of humidified, dehumidified, irrigated, evapotranspiratad water and water contents of media and plants increased with increasing relative humidity. Since the water consumption required to produce plug seedlings in CTPS dec1eased with decreasing relative humidity, the available water utilization efficiency of CTPS increased with decreasing relative humidity. CTPS showed high available water utilization efficiency of 0.92 - 0.97 if dehumidified water in CTPS was recycled. The development of CTPS with recycling system of dehumidified water will not only reduce the water consuming for the production of transplants but contribute to the establishment of plant production economizing in water consumption.

• Journal of fish pathology
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• v.5 no.2
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• pp.77-85
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• 1992

This study was carried out in order to investigate the immunosuppressive factor and immune response of color carp. The protection and serum antibody production of juvenile color carp aganist Aeromonas hydrophila were investigated on the effect of temperature differences and injected several aquatic drugs, i.e. Hydrocortisone, Oxytetracycline, Chloramphenicol and Ascorbic acid. The fish were injected intraperitoneally with 1mg/fish of HKC and FKC at three different temperature conditions as $16^{\circ}C$, $24^{\circ}C$, and $32^{\circ}C$ respectively. There were induced better protection and serum antibody production in the fish which had been kept at $24^{\circ}C$ than in the fish which had been kept at $16^{\circ}C$ and $32^{\circ}C$. The FKC immunized fish were followed 24 hrs later with intraperitoneal injection of 40mg/kg body weight of Hydrocortisone, 60mg/kg body weight of Oxytetracycline. 60mg/kg body weight of Chloramphenicol and 30mg/kg body weight of Ascorbic acid, respectively. The control fish were injected PBS only. The fish given the above aquatic drugs reduced serum antibody production level and protection rate when compared to control fish. As the results, immune response of juvenile color carp immunized FKC at $24^{\circ}C$ was more effective than $16^{\circ}C$ or $32^{\circ}C$ and immune response of juvenile color carp injected several aquatic drugs which was seemed to be immunosuppressive factor.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.447-459
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• 2013

Many problems need to be solved before vision systems can actually be applied in industry, such as the precision of the kinematics model of the robot control algorithm based on visual information, active compensation of the camera's focal length and orientation during the movement of the robot, and understanding the mapping of the physical 3-D space into 2-D camera coordinates. An algorithm is proposed to enable robot to move actively even if the relative positions between the camera and the robot is unknown. To solve the correction problem, this study proposes vision system model with six camera parameters. To develop the robot vision control algorithm, the N-R and EKF methods are applied to the vision system model. Finally, the position accuracy and processing time of the two algorithms developed based based on the EKF and the N-R methods are compared experimentally by making the robot perform slender bar placement task.

• Korean Journal of Materials Research
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• v.2 no.2
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• pp.85-94
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• 1992

The size, morphology and distribution of pores which affect on the physical properties of thermal barrier coatings were investigated to find the relationship with spraying parameters. The plasma-sprayed zirconia coatings contained numerous micropores as well as macropores which were appeared as spherical and irregular pores, and cracks. The pore formation process and its characteristics were varied with spraying distance. Porosity itself was varied with spraying parameters such as spray gun current, gas flow rate and the gas used(Ar or $N_2). The Porosity of coatings was ranged from 10 to 18% with the variation of spraying conditions. The relative hardness measured by the scratch test, showed strong dependence on the porosity of coatings rather than spraying parameters.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.123-133
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• 2011

The objective of this study was to find optimal nutrient condition of container seedling production of two tropical species for high seedling quality. This study was conducted to investigate photosynthesis, chlorophyll fluorescence, chlorophyll contents, and growth performances of container seedlings of Eucalyptus pellita and Acacia mangium growing under four different fertilization treatments (Con., $0.5\;g{\cdot}l^{-1}$, $1.0\;g{\cdot}l^{-1}$, and $2.0\;g{\cdot}l^{-1}$ fertilization). E. pellita showed outstanding photosynthetic capacity, photochemical efficiency, and chlorophyll contents at $1.0\;g{\cdot}l^{-1}$ fertilization. Meanwhile, E. pellita showed the highest photosynthetic capacity, photochemical efficiency, and chlorophyll contents at $2.0\;g{\cdot}l^{-1}$ fertilization, as fertilization rate were increased, those of A. mangium increased. Like physiological characteristics, Both E. pellita at $1.0\;g{\cdot}l^{-1}$ fertilization and A. mangium at $2.0\;g{\cdot}l^{-1}$ fertilization were higher root collar diameter, height, biomass, and seedling quality index than other treatments. These results showed that E. pellita at $1\;g{\cdot}l^{-1}$ fertilization and A. mangium at $2.0\;g{\cdot}l^{-1}$ fertilization is optimal nutrient condition, respectively. Moreover, fertilization rate controlling is very important for growth and seedling quality of container seedling.

• Journal of Korea Technology Innovation Society
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• v.13 no.3
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• pp.538-557
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• 2010

Korean Government has supplied small-medium enterprises with various technology financing programs such as R&D grant." loans, equities, guarantees since 1980's. The purpose of this study is to render policy suggestions for policy makers by analysing problems with regard to regulations. The suggestions of this study are such as the following. First, the current three months of the fund formation period should be extended within six months for general partners to have enough time to raise funds in the current tough capital market situation. Second, the government's non priority loss devotion system should keep going to prevent general partner's moral hazard. Third, in order to fulfill the policy purpose that is to create globally well-known companies, the government investment ratio should scale up from the current 20% to 30% of the total fund size in that the stable capital supply for core technology commercialization, industrialization and globalization of companies is achieved. Finally, general partners of the New Growth Engine Fund should showoff their investment abilities to the potential investors such as institutional investors by accumulating all track records and know-hows that prove their specialities and implementing action plans to achieve the best result of their investment. This study provides general considerations of the selection procedure, the government investment ratio, the government priority loss devotion system and so on when formating the public funds.

• Korean Journal of Materials Research
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• v.5 no.2
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• pp.239-245
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• 1995

Mn-Zn ferrite thin films were deposited on $SiO_2(1000 \AA)/Si(100)$ by ion beam sputtering using a single ion source. A mosaic target consisting of a single crystal(ll0) Mn-Zn ferrite with a Fe metal strip on it was used. As-deposited films without oxygen gas flow have a wiistite structure due to oxygen deficiencies, which originated from the extra metal atoms sputtered from the metal strips during deposition. The as-deposited films with oxygen gas flow, however, have a spinel structure with (111) preferred orientation. The crystallization of thin films was maximized at the ion beam extraction voltage of 2.lkV, at which the deposited films are bombarded appropriately by the energetic secondary ions reflected from the target. As the extraction voltage increased or decreased from the optimum value, the crystallinity of thin films becomes poor owing to a weak and severe bombardment of the secondary ions, respectively. Crystallization due to the bombardment of the secondary ions was also maximized at the beam incidence angle of $55^{\circ}$. The as-deposited ferrite thin films with a spinel structure showed ferrimagnetism and had an in-plane magnetization easy axis.