• Journal of Positioning, Navigation, and Timing
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• v.3 no.2
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• pp.71-81
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• 2014

Time synchronization system using dual frequency bands is designed and the error sources are analyzed for alternative synchronized-pseudolite navigation system (S-PNS) which aims at military application. To resolve near/far problem, dual frequency band operation is proposed instead of pulsing transmission which degrades level of reception. In dual frequency operation H/W delay should be considered to eliminate errors caused by inter-frequency bias (IFB) difference between the receivers of the pseudolites and users. When time synchronization is performed across the sea, multipath error is occurred severely since the elevation angle between pseudolites is low so total reflection can be happened. To investigate the difference of multipath effects according to location, pseudolites are set up coastal area and land area and performances are compared. The error source related with tropospheric delay is becoming dominant source as the coverage of the PNS is broadening. The tropospheric delay is measured by master pseudolite receiver directly using own pseudorange and slave pseudorange. Flight test is performed near coastal area using S-PNS equipped with developed time synchronization system and test results are also presented.

• Steel and Composite Structures
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• v.1 no.3
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• pp.295-312
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• 2001

The purpose of this paper is to propose a new type of steel reinforced concrete (SRC) beam-column joints and to examine the structural performance of the proposed joints, which simplify the construction procedure of steel fabrication, welding works, concrete casting and joint strengthening. In the proposed beam-column joints, the steel element of columns forms continuously built-in crossing of H-sections (${\Box}$), with adjacent flanges of column being connected by horizontal stiffeners in a joint at the level of the beam flanges. In addition, simplified lateral reinforcement (${\Box}$) is adopted in a joint to confine the longitudinal reinforcing bars in columns. Experimental and analytical studies have been carried out to estimate the structural performance of the proposed joints. Twelve cruciform specimens and seven SRC beam-column subassemblage specimens were prepared and tested. The following can be concluded from this study: (1) SRC subassemblages with the proposed beam-column joints show adequate seismic performances which are superior to the demand of the current code; (2) The yield and ultimate strength capacities of the beam-to-column connections can be estimated by analysis based on the yield line theory; (3) The skeleton curves and the ultimate shear capacities of the beam-column joint panel are predicted with a fair degree of accuracy by considering a simple stress transfer mechanism.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.3
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• pp.19-28
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• 1995

This paper presents hull form design details and performance characteristics of the SWATH ship 'SEON JIN' built as an underwater test support ship. The hull form is developed systematically varing sets of 11 form parameters which define a unique hull under waterline. Using this geometry variation scheme we have generated a number of alternatives and selected the final hull which fulfills the design objectives and matches the design constraints. After selecting the final hull form we have investigated performances thoroughly through model tests, and confirmed through sea trials that the performance goals be achieved.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.21-29
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• 2014

In this paper, we propose an efficient Robot Performance System (RPS). For the proposed system, a soundboard was developed and inserted into the body of a humanoid robot to enable audio playback without an external playback device; the hardware required to enable the external storage device within the soundboard to remember the sound sources necessary for performances was developed. Furthermore, a specialized performance scenario planning software called Robot Performance Planning Development Program (RPPDP) was developed to allow users to search through a motion database for the robot's default motions, applied motions, and motions for special circumstances, allowing anyone to plan a robot performance at a low cost in a short amount of time.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.143-143
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• 2017

Wheat is one of the most important crops in production and consumption. Despite increasing of importance, the self-sufficiency of wheat is less than 2% in Korea. To improve yield potential and broaden the genetic pool of common wheat in Korea, introduction of alien germplasms into the Korean wheat breeding program is suggested. For effective utilization of the germplasm, we introduced total 1,195 germplasms from the world, which were provided by National Plant Germplasm System (NPGS, USDA) and evaluated the yield, field performances and agronomic traits for 8 years. Among 55 countries, germplasms from Canada, Ethiopia, Mexico and United States accounts for 78%, especially germplasms collected from United States accounts for 50%. Yield comparison of germplasms and collected region analysis indicate that the high yielding germplasms are collected from countries or states of particular range of latitude. The combination analysis of the yield and agronomic traits and the geographical information of collected region will be utilized for improving Korean wheat breeding programs.

• Archives of design research
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• v.11 no.1
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• pp.1-10
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• 1998

In the medieval age of Europe when the noble people of various regions enjoyed unique cultures and life styles where made by coachbuilders. Such coaches would later affect the styles of the earlier automobiles equipped with the driving engine. Later, as the gasolines engines began to be distributed, the automobiles could afford to be flexible in terms of size and weight, while their performances and designs began to be enhanced rapidly. The important aspect of earlier automobile manufacturing was the phased development of styling which represented the pure approach to functions as well as the historical background. It can be known that such a development of automobile styling reflected the concerned industrial advancement and social influences of each region. At this juncture of time when the massmotorized modern society's demands for automobiles are unlimited and diversified, this study was aimed at reviewing the fundamental implications of automobile designs over time.

• Convergence Security Journal
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• v.16 no.3_2
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• pp.55-63
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• 2016

The purpose of this study is that there viewing at the future development direction and awareness of the cultural contents industry targeting college students for the activation of the domestic cultural content industry. And we want to find the need of the security industry & Concert Hall Safety. Recent worldwide it has occurred 'Soft target' terror targeting unspecified civilian in the cultural space of theater and music venues, stadiums etc. But security and safety systems against terror in Korea are very deficient situation. US security market has increased sales significantly interest in increasing against crime and terrorism prevention and depending on the price cut and technology development. It is expected to require a security industry in a variety of applications to the cultural contents industry development about Korean pop music and theatrical performances, and internet and mobile games stc.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.1
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• pp.10-16
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• 2018

The Republic of Korea Marine Corps is planning to develop a new amphibious assault vehicle which is able to operate with higher water speed than current KAAV. In order to achieve a higher water speed for hydrodynamically bulff-body vehicles, it is essential to develop drag reduction strategies. In this paper, resistance characteristics including trim angles of amphibious assault vehicles with several appendage designs are investigated using a commercial CFD code, STAR-CCM+. The computed results are compared with experimental data conducted at the towing tank with 1:4.5 scaled model and show good correlation. Comparing with the results of bare hull, 3.4 % of hydrodynamic drag and 52 % of trim angle are reduced by the application of double angled bow flap and a hydrofoil attached at the transom.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.2
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• pp.70-77
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• 2010

In order to improve the efficiency of a main transformer in a train, the optimal operation of a cooling system is necessary. For the development of optimal control algorithms of a cooling system, mathematical models of a main transformer cooling system were developed. These include static and dynamic models of a main transformer, an oil pump, an oil cooler, and a blower. Static models were used to find optimal oil temperatures of the inlet and the outlet of a transformer. Dynamic models were used to predict transient performances of control algorithms of a blower and an oil pump. Simulation results showed good predictions of the static and the dynamic behavior of a main transformer cooling system. Therefore, mathematical models developed in this study may be effectively used for the development of control algorithms of a main transformer cooling system.

• Journal of the Korean Magnetics Society
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• v.27 no.3
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• pp.98-103
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• 2017

In this paper, an efficient closed-loop degaussing technique is proposed to control real-time degaussing currents required for a minesweeper. To achieve this, new principle and algorithm for controling degaussing currents are presented, and they are compared to conventional ones. To validate the proposed method, a minesweeper mockup is tested by means of a rigorous numerical simulation. Results show that the method successfully yields satisfactory degaussing performances for several course angle changes of the mockup.