• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.22 no.3
• /
• pp.8-16
• /
• 1986

The fishing conditions of flying squid, ommastrePhes barsram(Lesueur), in the North Pacific Ocean was studied based on the horizontal water temperature data, satellite data from NOAA and statistical data of flying squid fisheries which were collected from 1980 to 1984. The obtained results were as follows; 1. Since 1979, the Korean drift giIlnet fishery for flying squid was launched in North Pacific. Number of operating vessel and catch of flying squid increased gradually every year. The number of vessels were 111 and their annual catches were 42, 977 M/T in 1984. Therefore, Korean drift giIlnet fishery for this species has played an important role in the products of Korean high-sea fisheries. 2. In the beginning of the fisheries, fishing grounds was formed in the west of long. 1800E. In 1982, in consequence of the center which extended eastward, the fishing ground was formed long. 166$^{\circ}$W in the central North Pacific Ocean. Since 1983, the fishing grounds were formed as far as long. 161$^{\circ}$W. The range of general fishing season in the central North Pacific was from June to August. After september, fishing ground was shifted to the west, in the Northwestern Pacific. 3. The Predominant fishing season for the flying squid was August through January of the coming year. Optimum water temperature for flying sguid at surface layer in the Pacific Ocean ranged from 11 $^{\circ}$e to 17$^{\circ}$e in winter, 13$^{\circ}$e to 17$^{\circ}$e in spring, 12. 8$^{\circ}$C to 19.7$^{\circ}$e in summer and 1O.6$^{\circ}$e -18.7$^{\circ}$e in fall. 4. In summer, the Oceanographic condition in the North Pacific Ocean showed that the water temperature at surface layer was lower in 1980, 1983 and higher in 1981, 1982 and 1984 as compared with mean annual water temperature. 5. The characteristics df oceanographic conditions in the fluation, disformation, mixing and other factors of the Kuroshio and Oyashio currents, which have considerably influenced upon the water masses of the areas. 6. The data and information on surface thermal Structure interpreted from Infrared Satellite Imaginary from NOAA-7 and NOAA-8 are very available in estimating water temperature on the areas and investigating the major fishing grounds. 7. According to the fisheries statics of Japanese drift gilInet, the annual catches of flying squid considerably decreased from 225, 942 M/T in 1983 to 133, 217 M/T in 1984. 8. The fishing grounds in the central North Pacific in several fishing seasons were formed as follows: In June, the initial fishing season, the fishing grounds were formed in the vicinity of lat. 35 - 40oN, the central North Pacific east of 179$^{\circ}$E. In July, the fishing ground were formed in the wide arEa of the central North Pacific north of 400N and long. 174$^{\circ}$E-145$^{\circ}$W In Auguest, concentrative fishing operation carried out in :he central North Pacific north of 43$^{\circ}$N and East of 165$^{\circ}$W. On the other hand, in September, main fishing grounds were disappeared and moved to the west.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.44 no.4
• /
• pp.294-303
• /
• 2008

Squid jigging fishery is very important in that there are about 1,000 jigging vessels more than 10 tonnage and about 5,000 ones less than 10 tonnage in Korea. But the cost of oil which is used to light fishing lamps, goes significantly up to almost one hundred million won for 50 tonnage vessels and forty million won in case of vessels less than 10 tonnage. This cost has almost taken 40% of total fishing costs. That is, the fishing business condition of squid jigging fishery is recently in the very difficult situation. As oil price increases, the business condition of the fishery gets worse and worse. Therefore it is very urgent to develop an economical fishing lamp, to solve this problem of fishery's business difficulty. This research aims at developing a fishing lamp for squid jigging fishery using the light emitting diode which has very excellent efficiency and durability. We made a water tank with 20 meters width which is a shape of raceway to research behavioral characteristics of Japanese flying squid to LED light, and made an experiment to investigate optimum wave of LED light to lure squid. The method is to establish LED lamps on both ends of water tank and to observe squid's behavior. Colors and wave lengths of LED lamps, used in experiment, are red(634nm), yellow(596nm), green(523nm), blue(454nm) and white(454nm+560nm). In experiment for attractive capability of LED lamp to squids, Japanese flying squid are highly attracted to blue lamp and white lamp. However, they are dispersed to red and yellow lamps. In addition, Japanese flying squid have moved and stayed in both dark ends of water tank. When compared intermittent lamp with continuous lamp, Japanese flying squid are highly attracted to intermittent lamp when intermittent interval is 0.25 second.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.12 no.4
• /
• pp.460-468
• /
• 2009

The purpose of this study is propose an alternative for flight attendants to acquire equipment that could enhance the ability to adapt in flying conditions. Introducing and acquiring weapon system, such equipments should be deeply considered in multilateral aspects; reinforcements in the overall strategic status in the army, the ramifications that can contribute to military resources, and economic situations in the country. To do this, we first induced several criteria that can be used for evaluating alternatives. After that, we applied the analytic hierarchy process(AHP) approach to putting all factors into considerations in decision making for equipment acquirement. The results of this study are expected to have usefulness in formulating strategies and policies in selecting equipment acquisition alternatives for flight attendants.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.15 no.3
• /
• pp.149-157
• /
• 2020

Regarding previously-developed drone simulators, it was easy to check their flight stability or controlling functions based on the condition that their weight was fixed from the design. However, the drone is largely classified into two types that is the one with the fixed weight whose purpose is recording video with camera and racing and another is whole weight-variable during flight with loading the articles for delivery and spraying pesticide though the weight of airframe is fixed. The purpose of this thesis is to analyze the structure of drone and its flight principle, suggest dynamics-model-based simulator that is capable of simulating weight-variable drone and develop the simulator that can be used for designing main control board, motor and transmission along the application of weight-variable drone. Weight-variable simulator was developed by using various calculation to apply flying method of drone to the simulator. First, ground coordinate system and airframe-fixing coordinate system were established and switching matrix of those two coordinates were made. Then, dynamics model of drone was established using the law of Newton and moment balance principle. Dynamics model was established in Simulink platform and simulation experiment was carried out by changing the weight of drone. In order to evaluate the validity of developed weight-variable simulator, it was compared to the results of clean flight public simulator against existing weight-fixed drone. Lastly, simulation test was performed with the developed weight-variable simulation by changing the weight of drone. It was found out that dynamics model controlled various flying positions of drone well from simulation and the possibility of securing the optimum condition of weight-variable drone that has flying stability and easiness of controlling.

• Bulletin of the Korean Space Science Society
• /
• 2003.05b
• /
• pp.25-25
• /
• 2003

No Abstract, See Full Text

• International Journal of Aeronautical and Space Sciences
• /
• v.3 no.2
• /
• pp.82-87
• /
• 2002

Aerodynamic analysis of NACA wings moving with a constant speed over guideways are performed using an indirect boundary element method (potential-based panel method). An integral equation is obtained by applying Green's theorem on all surfaces of the fluid domain. The surfaces over the wing and the guideways are discretized as rectangular panel elements. Constant strength singularities are distributed over the panel elements. The viscous shear layer behind the wing is represented by constant strength dipoles. The unknown strengths of potentials are determined by inverting the aerodynamic influence coefficient matrices constructed by using the no penetration conditions on the surfaces and the Kutta condition at the trailing edge of the wing. The aerodynamic characteristics for the wings flying over nonplanar ground surfaces are investigated for several ground heights.

• Journal of the Korean Society of Safety
• /
• v.9 no.4
• /
• pp.17-28
• /
• 1994

Chip breaking is important in lathe work for maintaining good surface of the products and safety of operator. The purpose of this study is to investigate the performance of chip breaking and chip shape resulted from the carbide inserts with grooved type and obstruction type chip breaker. Experiments have been performed under the following cutting conditions, (1) constant cutting speed with variable depth of cut and feed rate, (2) constant depth of cut with variable cutting speed and feed rate. Also, the flying distance of chip and it's distribution have been investigated. As a results, good performance of chip breaking can be obtained for small radius of curvature and land width of grooved type chip breaker. And the thickness of chip increase with the increase of feed rate and decrease of cutting speed, and the chip breaking becomes easier with the increase of chip thickness due to the large deformation rate. Obstraction type chip breaker shows better performance of surface roughness than the grooved type. The flying distance of the chips over 90% are less than 1 meter, and the distance decreases as the feed rate decreases.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.1
• /
• pp.273-283
• /
• 2018

The purpose of this study is to analyze the optimum driver selection according to shaft intensity, shaft length and shaft weight that are determining factors of driver shot. To achieve the above purpose, the subject were participate with handicap zero 10 male pro golfer and mean score 90(handicap about 18) amateur 10 male golfer. The used club limited number 1 driver, we tested 24 driver which is shaft intensity, length, weight, total weight and swing weight. Dependent variable was strike ball speed, flying distance and head speed. The findings can be summarized as follows. First, There is a significantly difference in CPM. Ball speed, head speed and flying distance according to driver shaft intensity were found to be the best when CPM is 230<. Second, There is a significantly difference in shaft length. Ball speed, and head speed according to driver shaft length were found to be the best at 46 inch and flying distance were found to be the best at 45 inch. Third, There is not significantly difference in SW. Ball speed and flying distance according to driver shaft weight were found to be the best with 65g. In the case of head speed, it was the fastest with 50g shaft. Four, total variables were significantly difference between in pro and amateur golfer. In conclusion, there would be differences in individual physical condition but the best result was found with a driver of CPM 230<, shaft length 46inch, and shaft weight 65g.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.172-173
• /
• 2021

In recent, unmanned Aircraft Systems (UAS) have been widely used for various purposes, such as safety inspection, facility condition inspection, progress monitoring, in the architecture engineering, and construction (AEC) industry. This technology can provide visual assets regarding the conditions of construction jobsites as well as constructed facilities during flying over the point of interests. With the significant interests in this advancement, the recent studies have presented how the UAS can be applied fro different types of facilities (e.g., buildings, power genereation systems, roads, or bridges) to inspect the current conditions of them for safe operations as well as public's safety. This study reviewed the receent studies to document their scientific findings and practical contributions, as well as provided the overview of further implications for future studies.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.41 no.1
• /
• pp.61-69
• /
• 2013

In an evaluation process of aircraft flying qualities, a clear and concise application interface is important since an evaluation process requires numerous repeated evaluation. This flight evaluation program have implemented efficient flight evaluation user interface along with changed trim condition interface and composed of comprehensive evaluation interface have mounted all automated FQ evaluation modules that was selected to be compose of 14 items in respect of an unmanned fixed-wing aircraft. Accordingly when it is necessary to design the flight control system as well as to develop a FQ considered aircraft, this S/W can be utilized as a tool that is a useful test evaluation S/W with scalability and enable to reduce the time and the cost of verification and evaluation process.