• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.11 no.5
• /
• pp.41-46
• /
• 2011

Mobile Ad-Hoc networks (MANET) has been getting the spotlight in the area of the wireless networks because of its flexibility and salability, and developing of many applications with it. As a consequence, MANETs are required to process not only simple data traffics, but also multimedia traffics, which has some constraints on the performances. However, unlike wired-networks, the wireless networks have frequent route-disconnections due to some reasons such as channel errors and mobility. Such frequent link disconnections makes the delivery of multimedia traffics difficult. Even though there many researches on multimedia transmissions on various environments, the performances of multimedia transmissions over fading channel and mobility even using various routing protocols have not been evaluated. Therefore, this paper extensively simulates the MPEG-4 video transmission over fading channel environment with node's mobility. In addition, the performances with two routing protocols such as AODV and DSR are compared. Finally, the simulation results shows that DSR protocol has the better performances to deliver MPEG-4 traffic.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.8 no.1
• /
• pp.39-45
• /
• 2008

High-Rate Wireless Personal Area Networks (HR-WPANs) in IEEE 802.15.3 standard use a TIme Devision Multiple Access (TDMA) protocol to support isochronous traffic. Isochronous traffic requires a delay-bounded service. However, the HR-WPAN standard suffers from long access delay and association delay. In this paper, we propose an enhanced MAC protocol for the delay-bounded traffic. This proposed protocol provides a way that a central node is able to collect traffic status on all member nodes. Furthermore, by utilizing the information, a scheduling algorithm is also proposed in order to synchronize the instant of a packet transmission with that of the packet arrival. With the proposed protocol and algorithm, the delay of access and association can be reduced. Performance analysis is carried out and the significant performance enhancement is observed.

• Journal of Broadcast Engineering
• /
• v.25 no.4
• /
• pp.598-608
• /
• 2020

In this paper, we propose a color correction technique for images acquired through a multi-view camera system for acquiring a 3D model. It is assumed that the 3D volume is captured indoors, and the position and intensity of the light is constant over time. 8 multi-view cameras are used, and converging toward the center of the space, so even if the lighting is constant, the intensity and angle of light entering each camera may be different. Therefore, a color optimization function is applied to a color correction chart taken from all cameras, and a color conversion matrix defining a relationship between the obtained 8 images is calculated. Using this, the images of all cameras are corrected based on the standard color correction chart. This paper proposed a color correction method to minimize the color difference between cameras when acquiring an image using 8 cameras of 3D objects, and experimentally proved that the color difference between images is reduced when it is restored to a 3D image.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.335-335
• /
• 2011

곰팡이에 의한 감염과 바이오 필름 형성이 우리 인간에게 매우 유해하다는 것은 익히 알려진 바이다. 일례로, 이는 우리가 먹는 음식을 오염시키고 치아를 상하게 하며 수도관을 부식시키고 또 우리 몸속에 집어넣는 의료기기에서 자라 심각한 질병을 유발시키는 등 여러가지 문제를 일으킨다. 곰팡이 감염과 바이오 필름 형성을 막기 위해 항생제 및 화학물질 등을 이용하는 방법들이 있으나 저항성이 증가된 균주의 출현, 환경오염 등의 문제점을 유발시키고 있다. 따라서 좀더 지속적이고 환경친화적인 기술개발이 요구되어지고 있다. 강한 살균력이 있다고 알려져 있는 대기압 플라즈마는 이러한 기술개발에 적용해볼 필요가 있다. 본 연구에서는 상온 대기압 플라즈마를 만들어 내는 여러 타입의 장치를 이용하여 곰팡이 살균과 이스트 바이오필름 형성 저해에 대한 조사를 하였고 플라즈마 처리에 따른 곰팡이 세포들의 세포학적 분자생물학적 영향에 대해 조사해 보았다. 대기압 상온 플라즈마 제트는 대기중에서 방안의 온도로 플라즈마가 생성되며 이를 페트리디쉬위에 접종된 이스트(Saccharomyces cerevisiae) 위 10 mm에서 조사한 결과 2분 이상의 처리를 했을 때 바이오 필름형성을 하지 못함을 보였고 곰팡이(Neurospora crassa)포자에 처리했을 때는 처리시간에 비례하여 발아하는 포자수가 감소하고 포자의 모양도 수축되는 것으로 관찰되었다. 대기압 플라즈마 제트는 대면적이 아닌 국부적 살균으로 살균력은 보이나 그 효율성이 낮아 이를 보완하기위해 DBD 형식의 플라즈마 장치를 만들었으며 이는 페트리디쉬의 모든 면을 동시에 조사할 수 있는 장점이 있다. 다만 제트와는 달리 플라즈마의 생성구간이 넓고 얇아 시료와 2~3 mm 간격을 띄우고 조사하였다. 제트와 마찬가지로 살균의 효과를 보였으며 기존의 단점을 극복하여 동시에 더 많은 면적을 조사 할 수 있게 되었다. 이를 통해 플라즈마의 살균능력을 직접 확인하였고 앞으로 더 많은 실험과 연구를 통해 일련의 과정들에 대한 원인을 규명하고자 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.9 no.3
• /
• pp.69-74
• /
• 2009

A novel protocol is proposed to achieve sub-carner-based rate adaptation in OFDM-based wireless systems. The protocol requires the addition of one OFDM symbol to the Clear-to-Send (CTS) packet defined in the IEEE 802.11 standard_ When receiving a Ready-To-Send (RTS) packet, the receiver determines the number of bits to be allocated in each sub-carrier through channel estimation. This decision is delivered to the sender using an additional OFDM symbol. That is, bit-allocation over sub-carriers is achieved using only one additional OFDM symbol. The protocol also provides an error recovery process to synchronize the bit-allocation information between the sender and receiver. The protocol enhances the channel efficiency in spite of the overhead of one additional OFDM symbol.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.3
• /
• pp.143-148
• /
• 2015

In order to design and plan a city, the importance of collecting traffic information increases. However, current method to collecting traffic information by using sensors layed on the roads is not appropriate for exceptional cases such as national highway or newly planned city area, where sensors are already not layed. To scope the cases, the traffic information is estimated from traffic information of surroundings area. This paper develops portable traffic volume measuring equipment utilizing two or radar detector, so that more useful traffic information can be obtained in any environments. Furthermore, the system allows users to be able to instantly analyze gathered data on the site. The system has been tested in the field and proved the excellences theough the field test.

• Journal of the Korean Chemical Society
• /
• v.36 no.3
• /
• pp.366-375
• /
• 1992

The aminolysis of carbamates are studied MO theoretically using AM1 method. The results indicated that the reactivity is determined by bond-making and-breaking and steric effects; as a result the $B_{AC}2$ mechanism is favored due to favorable contribution of bond formation in agreement with experimental results. We found that although thermal 2＋2 reaction is forbidden, it becomes allowed when the total electrons involved are six in a four-center reaction and proceeds by a consecutive onestep mechanism. Comparison of activation barriers show that greater energy is required in breaking a sigma bond compared with the energy required for breaking a $\pi$ bond, by 17 kcal/mol and the six membered ring structure is favored about 5 kcal/mol sterically.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.2
• /
• pp.7-14
• /
• 2021

By changing the bulky monolithic services architecture to a microservices-based architecture, industries are managing the rising complexity of Autonomous Vehicles. However, the underlying communication mechanisms for the utilization and distribution of these microservices are incapable of fulfilling the requirements of the futuristic AV, because of the stringent latency requirements along with intermittent and short-lived connectivity issues. This paper proposes to tackle these challenges by employing the revolutionary information-centric networking (ICN) paradigm as an underlying communication architecture. This paper argues that a microservice approach to building autonomous vehicle systems should utilize ICN to achieve effective service utilization, efficient distribution, and uniform service discovery. This research claims that the vision of an information-centric microservices will help to focus on research that can fill in current communication gaps preventing more effective, and lightweight autonomous vehicle services and communication protocols.

• Journal of Broadcast Engineering
• /
• v.25 no.6
• /
• pp.935-943
• /
• 2020

In this paper, we propose a method using deep learning for high-resolution display of phase holograms. If a general interpolation method is used, the brightness of the reconstruction result is lowered, and noise and afterimages occur. To solve this problem, a hologram was trained with a neural network structure that showed good performance in the single-image super resolution (SISR). As a result, it was possible to improve the problem that occurred in the reconstruction result and increase the resolution. In addition, by adjusting the number of channels to increase performance, the result increased by more than 0.3dB in same training.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.5
• /
• pp.637-644
• /
• 2021

In general, in the fields of computer vision, robotics, and augmented reality, the importance of 3D space and 3D object detection and recognition technology has emerged. In particular, since it is possible to acquire RGB images and depth images in real time through an image sensor using Microsoft Kinect method, many changes have been made to object detection, tracking and recognition studies. In this paper, we propose a method to improve the quality of 3D reconstructed images by processing images acquired through a depth-based (RGB-Depth) camera on a multi-view camera system. In this paper, a method of removing noise outside an object by applying a mask acquired from a color image and a method of applying a combined filtering operation to obtain the difference in depth information between pixels inside the object is proposed. Through each experiment result, it was confirmed that the proposed method can effectively remove noise and improve the quality of 3D reconstructed image.