• Wind and Structures
• /
• 제12권4호
• /
• pp.333-347
• /
• 2009

Many tower-supported steel stacks have been constructed in Japan, primarily for economic reasons. However the dynamic behavior of these stacks under a strong wind is not well known and the wind load design standard for this type of a stack has not yet been formulated. In light of this situation, we carried out wind response observation of an operating tower-supported steel stack with and without a tuned-mass damper. The observation revealed the performance of the tuned-mass damper installed on the stack in order to control the wind-induced vibration. Based on the observed data, we performed a wind tunnel test of a specimen of the stack. In this paper we report the results of the wind tunnel test and some comparisons with the results of observation. Our findings are as follows: 1) the tuned-mass damper installed on the specimen in the wind tunnel test worked as well as the one on the observed stack, 2) the amplitude of the vortex-induced vibration of the specimen corresponded approximately to that of the observed stack, and 3) correlation between Scruton number and reduced amplitude, y/d, (y is amplitude, d is diameter) was confirmed by both the wind tunnel test and the observed results.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2022년도 추계학술대회
• /
• pp.337-340
• /
• 2022

SQL Injection 공격은 오래된 공격기법 중 하나로 웹 서비스에 대한 해킹 시도 유형 중에서도 높은 비중을 차지하고 있다. SQL Injection 공격은 데이터 노출 및 권한획득 등의 방법으로 현재까지도 해킹 시도가 많이 발생하고 있으며, 본 논문에서는 오픈소스인 ELK Stack을 활용하여 실시간으로 SQL Injection 공격 대응할 수 있는 로그 분석시스템을 구현하였다. 구현한 시스템을 통해 SQL Injection 공격에 대한 로그 데이터를 시각화하여 제공함으로써, 사용자는 공격의 위험도를 쉽게 파악할 수 있으며 신속하게 공격에 대비할 수 있을 것으로 기대한다.

• 한국전기전자재료학회논문지
• /
• 제16권1호
• /
• pp.77-82
• /
• 2003

The ac loss is an important issue in the design of high-Tc superconducting power devices such as transformers and cables. In these devices many Bi-2223 tapes are closely stacked together and exposed to alternating magnetic fields that can have different orientations with respect to a tape. In such arrangement the magnetization loss is influenced by the screening current induced in adjacent tapes and thus different from that in a single tape. This stacking effect was experimentally investigated by measuring the magnetization loss in a stack, which consists of a number of tapes. First the magnetization loss in the single tape was measured in order to confirm the reliability of the loss data measured in the stack. The results for the single tape coincide well will the loss characteristics described in other previous works. For the stack In parallel and longitudinal magnetic fields the measured loss is Independent of both the number of tapes and stacking type. The longitudinal magnetization loss Is well explained rather by the slab model for decoupled filaments. For the tall stack in perpendicular field the measured loss at low fields is greatly decreased, compared to the loss of the single tape. However the loss at high fields is unaffected. These loss behaviors in the tall stack are well described by the slab model for full coupling.

• 전자공학회논문지C
• /
• 제35C권7호
• /
• pp.69-77
• /
• 1998

In this paper, a controller is designed for efficient controlling of video data with object-oriented feature. The need of controlling video data in an object unit is on the rise for the reason of rapidly growing demand for high-quality video services. We propose a programmable architecture with stack buffers which can minimize a scheduling overhead by having separate buffes for genral data and return addresses. The buffers are veyr useful for move and copy operations for multitasking and task switching. The controller offers extended instructions that process several data types including 32bit integrer type. Operation speed of the controller is from 77MHz to 44MHz.

• 정보처리학회논문지D
• /
• 제17D권4호
• /
• pp.297-310
• /
• 2010

최근에 콘콜릭 테스트이라 불리는 새로운 테스팅 방법이 많은 관심을 받고 있다. 콘콜릭 테스팅은 높은 테스트 커버리지를 달성하기 위해 실제 프로그램 수행과 심볼릭 수행을 결합하여 테스트 데이터를 생성한다. CREST는 콘콜릭 테스팅을 구현한 대표적인 open-source 테스트 도구이다. 그러나 현재 CREST는 입력으로 정수형만 다룬다. 이 논문은 포인터형인 입력이 존재하는 경우에 자동 테스트 데이터 생성을 위한 새로운 규칙을 제안한다. 이 규칙들은 C 프로그램에서 주로 사용되는 다단계 스택 지향 포인터를 효과적으로 처리한다. 또한, 이 논문에서는 제안 된 규칙을 구현한 vCREST라 불리는 도구에 대해 기술하고 C 프로그램에 적용한 결과도 함께 기술한다.

• 한국수소및신에너지학회논문집
• /
• 제19권5호
• /
• pp.367-376
• /
• 2008

To obtain the data of the pressure loss and differential pressure at the inside of the stack that was composed of 126 cells with 7,500 cm2 electrode area, 75kW molten carbonate fuel cell system has been operated. Computational fluid dynamics was applied to estimate reactions and thermal fluid behavior inside of the stack that was adopted with internal manifold type separator. The pressure loss coefficient K showed 72.29 to 84.01 in anode and 6.34 to 8.75 in cathode at low part of cells at the inside of 75 kW MCFC stack respectively. Meanwhile, the pressure loss coefficient of the higher part of cells at the interior of the stack showed 15.36 and 56.44 in anode and cathode respectively. These results mean that there is no big total pressure difference between anode and cathode at the inner part of 75 kW MCFC stack. This result will be reflected in 250kW MCFC system design.

• 한국수소및신에너지학회논문집
• /
• 제24권1호
• /
• pp.84-90
• /
• 2013

The hydrogen or oxygen gas producted by electrolysis become many bubbles in the electrolyte, but exact data on the behavior of these bubbles in the separator of an electrolysis stack didn't become known. In this study, the flow visualization experiment on the behavior of bubbles in the flow pattern of the array type separator is performed by using of a visible alkaline electrolysis stack and a stereoscopic microscope. As the results, a fine size bubbles adhered to the surface of the flow pattern grow to large sized bubbles until each bubble's buoyance is lager than the sum of external force and weight. And then the large bubbles flow into the upper area of the separator. Bubbles adhered to the surface of the vertical flow pattern grow quickly than them adhered to the surface of the horizontal flow pattern. Also, he electrolysis efficiency is declined because many multi-size bubbles occupied the wide volume in the flow pattern.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.52.1-52
• /
• 2001

System establishment using a network may be a decisive factor both for creating a flexible production system and increasing reliability and serve as a basis for setting up of a management system that will make the designing, maintenance, and repair easier. It is therefore imperative to develop a protocol which is simple to use for communications and connections among different devices. The objectives of this study is to establish communications protocol stack that will enable to conduct an effective monitoring of production facilities and to secure flexibility of reduction control system, and to improve the working ratio of the production facilities by centralization of communications system through effective collecting and storing of the diversified data of multi-type and multi-device production facilities.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권8호
• /
• pp.924-931
• /
• 1999

Most conventional protection relays are based on processing information in the spectrum that is close to or at power frequency. It is, however, widely known that faults on transmission lines produce frequency components of a wide range. High frequency signals caused by sudden changes in system voltage that occurs in the immediate post-fault period are generally outside the bandwidth of receptibility of most protection scheme. In this respect, a specially designed stack tuner is connected to the coupling capacitor of CVT, in order to capture the high frequency signals. Digital signal processing is then applied to the captured information to determine whether the fault is inside or outside the protected zone, and to discriminate the fault type. In this paper, modal transform is not applied to fault generated signals, because signals which are converted by modal transform are not have an information of each phase any longer. Instead, using peak voltage value of data windows is able to discriminate fault type. The paper concludes by presenting fault detection and discrimination of various faults on transmission line which are based on extensive simulation studies carried out on a typical 154kV Korean transmission line, using the EMTP software.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
• /
• pp.813-816
• /
• 2009

A commercial-scale RDF boiler that its burning capacity is 400 kg-RDF/hr and steam production capacity is 2 ton/hr. It has a chain type stoker and waste heat recovery system. Heat exchanger is vertical water-pipe so that soot blowing and removal is convenient during operation. Dry scrubber, bag filter and activated carbon tower have been installed for the reduction of air pollutant gases and dust. Analysing data of pollutants from stack such as $SO_x$. $NO_x$ and dioxin shows so good results that the boiler system could comply the regulated emission limits.