• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제53권3호
• /
• pp.175-181
• /
• 2004

In order to increase the coupling efficiency of the Power and Phase of the active Phase way antenna, we have fabricated the active phased-array antenna which is coupled by the transmission line, and investigated the relationship between the length of the coupling transmission line and coupling power and phase. The following three types of driving method -(1) giving the frequency difference between the two active antenna, (2) applying the input signal to the one side of the two antennas, and changing the eigen frequency of the other side antenna, (3) appling the different phase inputs to the active antennas was investigated. The experimental results showed that the interval of the antenna elements has not affected the power and the phase of the antenna.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 B
• /
• pp.1263-1265
• /
• 2004

RF-ID system is one of the very interesting field not only in a technical and economical point of view but also that people are still trying to realize lossless power transmission. This paper has a purpose on the efficient power transmission at the passive type IDcard by using wireless power transmission system. The most difficult but important part of the passive type RF-ID system is building the system that supplies power from Reader-antenna to IDcard-antenna. To check what is the most efficient way to deliver power depending on what kind of specifications of the power-amp in reader, antenna and antenna in IDcard is for operating IDcard circuit efficiently receiving the power from reader-antenna. For this, we used 125kHz sinewave for RF signal as a basic specification, OP-amp for amplifying signal and power-amp for amplifying power, loop type antenna.

• Acta Via Serica
• /
• 제8권2호
• /
• pp.79-94
• /
• 2023

The purpose of this study is to examine the descriptions of the transmission of plague along the Silk Road in Orhan Pamuk's 2022 novel Nights of Plague. Pamuk won the Nobel Prize in Literature in 2006, the first prize for Turkish literature. Pamuk's vast knowledge of epidemiological history, which has long fascinated him, comes to life in this novel as he describes the characters' battles against the plague in the East and West and how the plague was brought to the islands and spread along the Maritime Silk Road. One of the most important trade routes in human history, the Silk Road was not only a link between East and West trade and cultures but also a route for the transmission of bubonic plague during the medieval period onwards. It was this epidemic that contributed to the decline of the Silk Road. In the novel, a plague originating in China strikes the Ottoman coastal cities of Smyrna and Mingheria on its way to Europe via India. The epidemic is contained in Smyrna but the death toll spirals out of control when the plague reaches the island of Mingheria by sea. The spatial setting of the novel is an island, which means that it communicates with the outside world by sea. The only way the plague could have spread to an isolated island was by ship. Rats from different ports and ships would have traveled to other parts of the world or even countries to spread the plague. In Nights of Plague, the fact that the plague reached Mingheria via the maritime Silk Road is also proven by the route of the ships and various narratives. The novel confirms what many scholars have argued, that the Silk Road brought various goods from the East to the Roman Empire, along with deadly diseases, and that the sea routes were an important way for the plague to travel and spread.

• 정보보호학회논문지
• /
• 제23권2호
• /
• pp.299-305
• /
• 2013

물리적 일방향 자료전달 기술은 망간 분리 기술 중 하나로 외부망에서 내부망으로의 데이터 전송회선 자체를 제거하여 외부망을 통한 침입 가능성을 원천적으로 차단한다. 하지만 이로 인해 물리적 일방향 자료전달 기술을 적용하면 양방향 통신을 기반으로 제작된 레거시 서비스를 사용할 수 없다. 레거시 서비스를 운용하기 위해서는 서비스를 지원하는 별도의 에이전트가 필요하다. 하지만 에이전트 개발은 내부 프로토콜 공개, 추가적인 비용 등의 어려움이 존재한다. 본 논문에서는 이런 문제를 해결하기 위해 현장 제어시스템에서 운용 중인 레거시 서비스를 분석하여 세 가지 형태로 분류하였다. 분류를 바탕으로 세 가지 형태의 서비스를 지원하는 에이전트를 자동 생성할 수 있는 방법과 이를 기반으로 한 에이전트 자동 생성 도구의 설계를 제시한다.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2003년도 춘계종합학술대회
• /
• pp.218-221
• /
• 2003

가입자선로 환경이 ADSL 전송성능에 미치는 요인을 조사하기 위해서 본 논문에서는 의사선로를 구성하여 실험, 분석하였다. ADSL 전송성능 저해요인중 선로의 거리, 케이블의 접속 방법, 브리지 탭, 인입선의 종류에 따르는 비교분석과 AM 방송 잡음의 영향에 대하여 관찰하였다. ADSL의 전송성능을 유지하기 위하여는 현재의 동선 선로를 사용하는 경우 환경조건에 적합하도록 개선하여 활용해야 할 것이며, 점차적으로는 전송특성이 우수한 광 케이블로 대체하여 나가야 할 것으로 판단된다.

• 한국정보과학회논문지:정보통신
• /
• 제34권2호
• /
• pp.100-109
• /
• 2007

가용대역폭(Available Bandwidth) 측정 기법을 이용한 기존 스트리밍 프로토콜들(Streaming Protocol)은 가용대역폭을 측정하는 것에 있어서 정확성이 떨어지는 문제와 측정 속도가 느리다는 문제를 가지고 있다. 본 논문에서는 기존 가용대역폭 측정방법에 대한 연구가 가지고 있는 한계점을 극복하기 위해서 새로운 가용대역폭 측정 기법인 NABO(New Available Bandwidth measurement based on One-Way Delay)를 제안한다. NABO는 OWD(One-Way Delay)에 포함되어 있는 경쟁 트래픽이 없을 때의 전송 지연시간을 추출해 내고, 그 이후에 OWD에 반영하는 전송 지연시간을 제외한 경쟁트래픽에 의한 가변적인 지연을 측정함으로써 경쟁트래픽의 양을 측정한다. 이를 통해서 병목링크의 고정대역폭에서 경쟁트래픽의 대역폭을 제외한 가용대역폭을 정확하고 빠르게 산출한다. NABO의 성능을 검증하기 위한 실험 결과, 제안한 NABO가 다양한 네트워크 환경에서 스트리밍 서비스(Streaming Service)의 요구사항을 효율적으로 만족시킬 수 있음을 확인할 수 있었다.

• 대한기계학회논문집A
• /
• 제22권3호
• /
• pp.504-518
• /
• 1998

Degree-Of-Freedom(DOF) for most power transmission system varies according to the operation status which consists of friction elements to change the power flow or to adjust the speed ratio such as clutches, brakes or one-way clutches. To simulate the dynamic characteristics of automatic power transmission system which is a typical example of such a variable DOF systems, many sets of governing equations and complicated phase decision routines are necessary. In this paper dynamic constraint theorem is derived explaining the torque transmission characteristics during the clutch engagement process and a robust stable algorithm is developed describing this phase transition phenomenon effectively by introducing the concept of direct torque and virtual damping. Finally, applying this algorithm to a passenger car automatic transmission gear consisting of several friction elements, an efficient simulation methods for such a complex system will be suggested that is very simple and systematic.

• 전기학회논문지
• /
• 제66권10호
• /
• pp.1454-1459
• /
• 2017

In spite of continuous increase of electric power demand and new generation plants, it is very difficult to install new transmission line. Therefore, it comes to be difficult to operate the power system stable, so it is required to find another way to get new transmission capacity. Because HVDC transmission system installation is the one of the best option for us, we have undertake the HVDC project in mainland. Buckdangjin-Goduck HVDC project(500kV, 3GW) is currently under construction and Eastern Power HVDC project(500kV, 8GW) is under the study for technical specification. Both of them have the Run-up SPS function for taking action of 765kV Transmission line fault. The Run-up SPS function increases the active power output of the HVDC rapidly when the transmission line between the power plant and network is tripped, thereby preventing the generator from overspeed and improving the power system stability. In this paper, we propose MEAC(Modified Equal Area Criteria) method based on traditional EAC method to quantitatively evaluate the effect of the HVDC run-up SPS function on the power system stability improvement.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권7호
• /
• pp.2365-2382
• /
• 2014

While single-user spatial multiplexing multiple-input multiple-output (SU-MIMO) allows spatially multiplexed data streams to be transmitted to one node at a time, multi-user spatial multiplexing MIMO (MU-MIMO) enables the simultaneous transmission to multiple nodes. However, if the transmission time required to send packets to each node varies considerably, MU-MIMO may fail to utilize the available MIMO capacity to its full potential. The transmission time typically depends upon two factors: the link quality of the selected channel and the data length (packet size). To utilize the cumulative capacity of multiple channels in MIMO applications, the assignment of channels to each node should be controlled according to the measured channel quality or the transmission queue status of the node.A MAC protocol design that can switch between MU-MIMO and multiple SU-MIMO transmissions by considering the channel quality and queue status information prior to the actual data transmission (i.e., by exchanging control packets between transmitter and receiver pairs) could address such issues in a simple but in attractive way. In this study, we propose a new MAC protocol that is capable of performing such switching and thereby improve the system performance of very high throughput WLANs. The detailed performance analysis demonstrates that greater benefits can be obtained using the proposed scheme, as compared to conventional MU-MIMO transmission schemes.

• 한국철도학회논문집
• /
• 제14권1호
• /
• pp.19-23
• /
• 2011

고속철도 차량의 고속화, 경량화와 더불어 승객의 실내 소음을 줄이기 위한 많은 연구가 진행되고 있다. 고속철도 차량의 실내 소음을 줄이는 방법으로 차량 구조물의 차음 성능을 향상시키는 연구가 중요시 되고 있으나 투과손실 연구는 많은 경제적 비용이 요구된다. 따라서 본 연구에서는 소형 잔향실을 이용하여 고속철도 차량의 투과손실을 측정할 수 있는 방법을 연구 하였다. 연구 결과 소형 잔향실을 이용한 차음성능 연구가 대형 잔향공간을 이용한 투과손실 결과 대비 신뢰성 있는 결과를 도출 하였다.