• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.291-297
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• 2019

The world's leading industrialized nations are improving their national science and technology capacity through the continuous expansion of national R&D investment and the improvement of performance in accordance with the trend of the fourth industrial revolution. As rapid technological development following technological convergence necessitates a preemptive response to a new paradigm, the importance of securing high technology that affects the national competitiveness is increasing day by day. Core technologies and future new technologies that affect national competitiveness can be seen as a measure to upgrade the nation's innovative capabilities. In particular, the core technologies and future new technologies to prepare for changes in a security environment and future battlefields are very important in the defense sector that develops weapons systems. In the defense sector, the core technologies based on the military weapons systems are identified, and future new technologies that use the best technologies of the private sector for national defense, not on the needs of develops weapons systems, are derived. This study examined the characteristics of core technology and future new technology of defense ground unmanned systems, conducted a comparative study through empirical analysis, and concluded that strategic technology planning and research and development are needed according to the core technology and future new technology characteristics.

• Journal of Cadastre & Land InformatiX
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• v.50 no.2
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• pp.155-168
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• 2020

Open source is a key growth engine of the 4th industrial revolution, and the continuous development and use of various algorithms for image processing is expected. The purpose of this study is to examine the effectiveness of the UAS image processing open source based algorithm by comparing and analyzing the water reproduction and moving object filtering function and the time required for data processing in 3D reproduction. Five matching algorithms were compared based on recall and processing speed through the 'ANN-Benchmarks' program, and HNSW (Hierarchical Navigable Small World) matching algorithm was judged to be the best. Based on this, 108 algorithms for image processing were constructed by combining each methods of triangulation, point cloud data densification, and surface generation. In addition, the 3D reproduction and data processing time of 108 algorithms for image processing were studied for UAS (Unmanned Aerial System) images of a park adjacent to the sea, and compared and analyzed with the commercial image processing software 'Pix4D Mapper'. As a result of the study, the algorithms that are good in terms of reproducing water and filtering functions of moving objects during 3D reproduction were specified, respectively, and the algorithm with the lowest required time was selected, and the effectiveness of the algorithm was verified by comparing it with the result of 'Pix4D Mapper'.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.282-286
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• 1990

Currently, mechanization and automation have been introduced into rice harvest and drying process due to the shortage of man power. After rice cultivars, Chucheong and Milyang #23 were cutted with manual method (H1) or harvested with combine (H2), the threshed grain were dried in natural sun-drying (D1), in natural air in-bin system (D2), or in contineous hot-air drier (D3). We have evaluated grain losses, operation hour, and grain quality on each harvest and drying methods. Shattering loss during harvesting with combine was not dirfered significant from that of manual method, but threshing loss was 1.2% higher in combine harvest than in manual. Operation hours required for combine harvest was 3.5 times faster than for manual, even without head threshing. There was a significant difference bel ween cultivars in harvesting loss, which Milyang #23, a Tongil rice had two times more grain loss than Chucheong, a Japonica rice. Drying hours required to reduce to 14% grain moisture content were ten days for H1D1, 5-9 days for H2 D1, 2-3 days for H2D2, and only 15 hours for H2D3, respectively. In grain quality, complete grain ratio after dehulling was decreased about four percent in H2D3 compared to H1D1. while it was lower in Milyang #23 than in Chucheong, Hot-air drier increased occurence of cracked and broken grain. Combine harvest increased significantly these incomplete grain ratio of :Milyang #23, but not Chucheong.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.749-762
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• 2019

In recent years, in urban areas, underground of roads are being promoted in order to resolve traffic congestion and to secure green spaces, and due to the low ratio of large vehicles, they are planned or constructed as road tunnels for small cars only. In addition, the tunnels being built in the city is a tendency to be enlarged to play the role of main roads. Accordingly, the capacity of the ventilation system is increasing and various ventilation methods are required, and the importance of maintenance after the completion of the tunnel such as the operating cost of the ventilation system is emphasized. Therefore, the need for optimization of the operation stage for reducing the power consumption of the ventilation system and the study of the ventilation system operation control logic is increasing. In this study, the study on the necessity of the optimization of operation stage and control logic of the ventilation system was carried out to realize the energy-saving operation for the small car only passing through tunnels which is applied of ① jet fan and combination ventilation system (② jet fan + air purifying equipment, ③ jet fan + vertical shaft, ④ jet fan + supply air semi-transverse). As a result of this study, there can be various operating combinations in the case of the combined ventilation system, and even though the amount of ventilation air is the same, the operating power varies greatly according to the operating combinations. It was found that operating the axial fan first rather than the jet fan first operation method has an effect on power saving.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.4
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• pp.93-103
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• 1999

The steady-state performance analysis program for turboprop engine which was used for a small, middle industrial aircraft and a basic trainer aircraft was developed and linear Gas Path Analysis method was applied to Engine Health Monitoring for Turboprop engine. This program was compared with TURBOMARCH program which is well known with performance and power according to flight Mach No. at the standard atmospheric condition to prove a steady-state performance analysis program. From the result, inlet, exit temperature and pressure of each component had error within 3% and especially power according to flight Mach No. had error within 2.4% so that this program could be assured. To make sure if linear Gas Path Analysis is reasonable four cases were selected. The first is the case that fouling is occurred in compressor only. The second is the case that fouling is occurred in compressor and erosion is occurred in turbine. The third is the case that erosion is occurred in both compressor and turbine and power turbine at the same time. Finally, the case that fouling and erosion are occurred in compressor, compressor turbine and power turbine was selected. Different parameters were selected impartially among the independent parameters so that the effect of measurement parameter selection was observed. From the result, the more measurement parameters the smaller RMS error and even though the number of measurement parameters was the same, the RMS error was obtained differently according to which measurement parameters were selected. The case using eight instrument parameters of case IV-4 had small error comparably and was economic and it was important to select optimal number of measurement and optimal measurement parameters.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.533-535
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• 2002

The new watering system for the cabinet type of soybean sprouting equipment was developed. It was made of one siphon $({\Phi}35 mm)$, one well bucket $(13{\times}10{\times}10\;cm)$ that its weight-center is changed by water level, and bottle-neck water tank (bottom: $18.5^W{\times}32^L{\times}29^H\;cm$, top: $14^W{\times}14^L{\times}25^H\;cm)$. The watering system can be automatically watered more than 750 mL/sec without electric supply. The soybean sprouting equipment is consisted of the watering system and nine sprouting buckets. In addition siphon phenomena brought about easily by narrowing same as bottle-neck shape top portion of water tank that inserted a siphon. The equipment with the watering system may be produced more than three box a day in the condition of $25{\pm}1^{\circ}C$, and $6{\sim}7$ watering times a day.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.351-358
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• 2016

An Electrical Point Machine (NS:New-type Switch), which is equipped and operated at railways in Korea, has been used since the 1960s after being imported from Japan. On the other hand, although the mechanical configuration has improved the position motor control circuit, the electrical connection has not been improved, so NS may have a problem, such as the interlocking system of automatic train operation. In addition, NS is the most vulnerable part in the railway system and a huge train accident may occur due to minor defects. The existing NS wiring set of the circuit controller should be checked only if fixed. Therefore, an excessive inspection time only by a Railroad Signal expert is required. In this paper, the improvement of electrical connection in a NS wiring set, such as the position motor control circuit, was developed and the prototype was installed at Seoul Metro in the distance to go section. The results can be used to help make appropriate adjustments. The improvement of the NS wiring set enhance the maintenance efficiency, passenger service and the stability of the signal system as well as reducing the maintenance cost.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.493-501
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• 2016

In this study, core technologies of a traction system on a mountain tram operating on the track of mountain road full of sharp curves and steep gradients were developed. In domestic mountain resort areas, sometimes the transportation service is not provided in winter because of ice and heavy snow on roads, so a mountain railway service independent of the climate and geographic conditions is needed. A traction system was designed taking into account of the power of a traction motor to climb the gradient of 120 ‰, which is common in domestic mountainous areas. and power transmission system was designed to consider the installation space for the traction system. In addition, a reduction gear and a propeller shaft were developed. An elastic pinion was developed and applied to the rack & pinion bogie system for steep gradient so that noise and vibration generated by contact between the steel gears could be reduced. Impact comparison tests showed that the vibration level of the elastic pinion is one-third lower than that of previous steel pinion. Independent rotating wheels and axles were developed for the bogie system to operate on the sharp curve of a 10 meter radius. In addition, the band braking system was developed to enhance the braking force during running on the steep gradient. A test for the braking force showed it exerts the required braking force. The performance of the developed core components were verified by the tests and finally they were applied to the bogie system running on the track of steep gradient and sharp curve.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.703-709
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• 2017

Korea Utility Helicopter(KUH) is a project to replace the aging helicopter presently being operated by the military with a domestic helicopter. The auxiliary power unit is a device that supplies emergency power to the system by an alternator installed when the main generator fails and the start motor converts the electrical energy of the battery into mechanical rotational energy to rotate the auxiliary power unit engine. With continuing power and operation, defects of the starting motor were found and improvements were carried out to solve it. In the failure mode analysis, the causes of possible defects were classified into 5 categories. Analysis of the 5 factors revealed that the main cause of defects is mechanical wear, which was found to be related to spring pressure. 250 tests were conducted through the theoretically determined pressure and regression analysis was performed with 4 sampling.The results showed that pressure was related to wear rate. In conclusion, early wear and breakage due to wear can be controlled through spring force and test showed the prediction of wear and the validity of the result were confirmed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.3
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• pp.35-42
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• 1979

Experiments were conducted to find out the labor saving efficiency and optimum seeding rate and fertilizer level when newly invented Barley Rotor Caster was used in wheat sowing on paddy field. It decreased the labor for sowing by 66~77% compared with conventional sowing method. And the optimum. seeding rate was considered to be approximately 20$\ell$Q per 10a in standard fertilizer level and optimum fertilizer level to be 18-12-12kg/10a, $N-P_2O_5-K_2O$ respectively.