• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.11a
• /
• pp.192-193
• /
• 2015

Construction Cycle Trend Survey, which survey total value of orders and realized amounts monthly, is a valuable statistics that used to quick grasp or forecast the trend of domestic construction business. In recent periodical survey quality diagnoses, few professional users named a problem that Construction Cycle Trend Survey could not get together with the current state of the construction industry. This study examined weather Construction Cycle Trend Survey reflects the economic sentiment of construction business or not. Paired t test was performed between Construction Cycle Trend Survey and Construction Business Survey Index (CBSI), and significant differences were verified.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.40 no.6
• /
• pp.562-566
• /
• 1991

Many research and development activities have found that Superconducting Generators (SCG) have advantages such as high efficiency, light weight, small size, large unit size and good steady-state stability over conventional ones. However the transient stability of SCG is comparable to that of conventional ones. One way to improve the transient stability of SCG is to apply quick-response excitation system to the SCG. For this purpose, an SCG with an electrothermal shield of short electric time constants should be developed. In this paper, a new electrothermal shield, called slitted electrothermal shield(SES), is proposed. The SES can easily transmit radiated heat into the ends of the shield as in the conventional electrothermal shields(CES) and can easily pass magnetic flux produced by armature and field windings. By finite element analysis and experimental test, the slitting effects of SES on magnetic shielding are compared. Good agreement is obtained between simulated and test results.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1650-1655
• /
• 2007

A lights-out detector, which helps the person in charge of maintenance make a quick judgment in the event of a failure of LED-type traffic lights, was explored/developed and installed/ tested, at Seoul Metro, after they developed a patented pilot product in 2005; and, a product improvement test was conducted to ensure reasonable maintenance of signaling facilities. Having better compatibility with existing circuit in use and displaying stable load current, the device makes the maintenance of lights-out detection and alert easier.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.7
• /
• pp.1074-1080
• /
• 2015

In the last decades, the increasing interest in unmanned aerial vehicle(UAV) for military, surveillance, and rescue applications made necessary the development of flight control theory and body structure more and more efficient and fast. In this paper, we describe the design and performance of a prototype hexarotor UAV platform featuring an inertial measurement unit(IMU) based autonomous-flying for use in bluetooth communication environments. The proposed system comprises the construction of the test hexarotor platform, the implementation of an IMU, dynamic modeling and simulation in the hexarotor helicopter. Furthermore, the hexarotor helicopter with implemented IMU is connected with a micro controller unit(ARM-cortex) board. The P-PD control algorithm was used to control the hexarotor. We used the Matlab software to help us to tune the P-PD control parameters for quick response and minimizing the fluctuation. The control simulation and experiment on the real system are implemented in the test platform, evaluated and compared against each other.

• Journal of Ocean Engineering and Technology
• /
• v.26 no.6
• /
• pp.1-6
• /
• 2012

The purpose of this paper is to present a rational method for analyzing, designing, or evaluating the spread mooring systems used with floating drilling units. This paper presents a validated model to calculate the catenary static configuration. A semi-resolution approach is presented in this paper that is capable of predicting the static performance of a caisson mooring system. The solution is derived as a function of only three parameters, which can be solved numerically by implementing different kinds of boundary conditions. The efficiency and accuracy of the method permit quick parametric studies for the optimal selection of the system particle, which is undoubtedly useful for a preliminary design. A number of numerical examples demonstrate the validity of the adopted approach. The paper contains a complete description of the test cases and reports the results in such a way that it can provide a "benchmark" test for users and programmers of computer codes for flexible riser analysis.

• International Journal of Reliability and Applications
• /
• v.18 no.2
• /
• pp.21-44
• /
• 2017

Accelerated life tests (ALTs) are frequently used in manufacturing industries to evaluate the reliability of products within a reasonable amount of time and cost. Test units are subjected to elevated stresses which yield quick failures. Most of the previous works on designing ALT plans are focused on tests that involve a single stress. Many times more than one stress factor influence the product's functioning. This paper deals with the design of optimum modified ramp-stress ALT plan for Burr type XII distribution with Type-I censoring under two stress factors, viz., voltage and switching rate each at two levels- low and high. It is assumed that usage time to failure is power law function of switching rate, and voltage increases linearly with time according to modified ramp-stress scheme. The cumulative exposure model is used to incorporate the effect of changing stresses. The optimum plan is devised using D-optimality criterion wherein the ${\log}_{10}$ of the determinant of Fisher information matrix is maximized. The method developed has been explained using a numerical example and sensitivity carried out.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.771-778
• /
• 2006

Before the Flap type GATE is introduced until, the Turnstile type GATE was plentifully used. The Turnstile type GATE is used plentifully from the Seoul metro, Busan Transportation Corporation and Korea Railroad Corporation. From the Turnstile type GATE, the micro switch breakdown is occurred by the contact of the micro switch which perceives a Turnstile rotation and the cam. The breakdown is cause of the passenger inconveniently. In order to prevent the breakdown which is caused by Micro switch contact, Microswitch support used the sensor in Turnstile rotation perception. The sensor which is used in test is Photo Sensor and Reed Sensor two type. The test result Reed Sensor was suitable in underground environment. When using the RF card, RF card processing came to be quick

• Journal of the Korean Society of Clothing and Textiles
• /
• v.23 no.5
• /
• pp.645-653
• /
• 1999

본 연구의 목적은 미국 신속대응시스템의 요소별 사용현황을 조사하고 도입업체와 미도입업체의 신속대응시스템의 요소별 수준을 비교하며 신속대응시스템 도입업체와 미도입업체의 기업규모 제품종류를 비교분석하였다 조사방법은 미국의 103개 의류업체를 대상으로 설문조살르 하였고 자료분석은 기술통계와 t-test Fisher's Exact test를 사용하였다 신속대응시스템의 4요소는 상품기획, 재고관리, 정보공유, 유연한 생산체계이며 각 요소는 단위기술의 조합으로 측정되었다 신속대응시스템을 도입하고 있는 업체들은 미도입업체보다 모든 4요소의 도입수준이 유의적으로 높았다. 신속대응시스템을 도입업체들은 유연한 생산체계 요소에 대한 도입수준이 가장높게 나타났고 재고관리 요소에 대한 도입수준은 상대적으로 낮게 나타났다 신속대응시스템 도입업체는 종업원 500명이상인 대기업규모에 여성복업체에 가장 높은 비율을 나타내었고 미도입업체는 종업원이 10-19명 정도인 중소규모에 유아동복에 가장 높은 비율로 나타났다.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.885-887
• /
• 2003

The purpose of this investigation is to generate true orthophotos from high resolution satellite images. The major works of this research include 4 parts: (1) determination of orientation parameters, (2) generating traditional orthophotos using terrain model, (3) relief correction for buildings, and (4) process for hidden areas. To determine the position of satellites, we correct the onboard orientation parameters to fine tune the orbit. In the generation of traditional orthophotos, we employ orientation parameters and digital terrain model(DTM) to rectify tilt displacements and relief displacements for terrain. We, then, compute relief displacements for buildings with digital building model (DBM). To avoid double mapping, we detect hidden areas. Due to the satellite’s small field of view, an efficient method for the detection of hidden areas and building rectification will be proposed in this paper. Test areas cover the city of Kaohsiung in southern Taiwan. Test images are from the QuickBird satellite.

• Journal of the Korea Society of Computer and Information
• /
• v.23 no.12
• /
• pp.131-136
• /
• 2018

This paper proposes a computer-aided diagnostic algorithm in a non-invasive way. Currently, clinical diagnosis of jaundice is performed through blood sampling. Unlike the old methods, the non-invasive method will enable parents to measure newborns' jaundice by only using their mobile phones. The proposed algorithm enables high accuracy and quick diagnosis through machine learning. In here, we used the SVM model of machine learning that learned the feature extracted through image preprocessing and we used the international jaundice research data as the test data set. As a result of applying our developed algorithm, it took about 5 seconds to diagnose jaundice and it showed a 93.4% prediction accuracy. The software is real-time diagnosed and it minimizes the infant's pain by non-invasive method and parents can easily and temporarily diagnose newborns' jaundice. In the future, we aim to use the jaundice photograph of the newborn babies' data as our test data set for more accurate results.