• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.5A
• /
• pp.487-493
• /
• 2008

In this paper, we consider coded layered space-time architecture in MIMO-OFDM channels. Vertical Bell Lab Layered Space-Time(V-BLAST) scheme employing ordered successive interference cancellation(OSIC) algorithm provides very high spectral efficiency with low computational complexity. However, the error propagation is a major drawback constraining the overall performance of the V-BLAST system significantly. Based on this problem, we derive an improved detector using soft bit log-likelihood ratio(LLR) value. Simulation results show that the proposed detector outperforms the conventional V-BLAST scheme under spatially uncorrelated as well as correlated fading channels.

• Journal of Satellite, Information and Communications
• /
• v.5 no.2
• /
• pp.40-44
• /
• 2010

A layered coding scheme is one of the adaptive receiving techniques for unidirectional services such as multimedia broadcasting and multicasting services (MBMS), where we cannot utilize feedback information. The layered coding scheme can be used with hierarchical modulations by combining suitable code rates and modulation orders of each. In addition, it has been reported that hybrid and/or integrated satellite systems can effectively achieve transmit diversity gains by appropriate utilization of space time coding combined with turbo codes. This paper proposes a layered turbo coding schemes for hybrid and/or integrated satellite systems. We first introduce the system architecture and operational principle of the proposed scheme, and discuss the applicability.

• The Journal of the Acoustical Society of Korea
• /
• v.34 no.6
• /
• pp.470-478
• /
• 2015

A heuristic method treating a layered ocean bottom in a ray modeling is to use the plane wave reflection coefficient for multiple-layered structure, named an one-layer assumption in this paper. We examine the validity of one-layer assumption in the case of two-layered ocean bottom, and obtain a simple inequality condition depending on the sound speed ratio, the ratio of layer thickness to source-receiver range, and the grazing angle of first reflected ray. From this inequality condition, it is shown that an one-layer assumption can be applicable to ray propagation problems at mid frequencies. Finally, numerical experiments are performed in the ocean environment similar to the East Sea in Korea. Incoherent transmission loss is calculated by the geometrical beam model with the plane wave reflection coefficient for multiple-layered ocean bottom and compared with the result of SNUPE 2.0, which is a parabolic equation package developed in Seoul National University.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.5 no.4
• /
• pp.27-37
• /
• 2009

This paper is about the architectures of an extensible and scalable home automation system which is based on instant messaging. The extensibility is the most important feature of the system because there are very diverse appliances at home and they can be added or replaced with other products frequently. For the extensibility, we propose façade architecture for communication, distributed agent architecture for the system, layered architecture for agents, and bridge architecture for wrapping existing facilities. Using these architectures, we reduce the system complexity and get the extensibility to add new products with least cost. Furthermore, we also introduce our prototype system and show that it is extensible.

• Journal of Korean Society of Transportation
• /
• v.19 no.6
• /
• pp.19-31
• /
• 2001

In this paper, 3 layered architecture model and related design guidelines are proposed, which have been actually applied in our national ITS-Architecture design. The domain architecture as the 1st layer is to structure all ITS related domains for maximizing the co-operability in national level. The logical architecture as the 2nd layer is to structure all ITS related application-systems for minimizing duplications, conflicts and dead-zones in service level and maximizing the co-operability in application-system level. The physical architecture as the 3rd layer is to structure all IT(Information Technology) related physical resources for maximizing.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.4B
• /
• pp.695-703
• /
• 2010

In this paper, we propose an adaptive scalable encryption scheme for the layered architecture of SVC video. The proposed method determines an appropriate set of encryption algorithms to be applied for the layers of SVC by considering the importance and priority relationship among the SVC video layers. Unlike the conventional encryption method based on a fixed encryption algorithm for the whole video layers, the proposed method applies differentiated encryption algorithms with different encryption strength the importance of the video layers. Thereupon, higher security could be maintained for the lower video layer including more important data, while lower encryption strength could be applied for the higher video layer with relatively less important data. The effectiveness of the proposed adaptive scalable encryption method is proved by extensive simulations.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.12C
• /
• pp.1228-1237
• /
• 2002

Network management is composed of five major functional areas, fault, configuration, account, performance and security management in the ITU standards. Configuration management identifies, exercises control over, collects data from network element node system and provides data to the management systems. The proposed architecture is designed based on the Distributed Processing Environment of CORBA(Common Object Request Broker Architecture) Spec v2.3. In this paper, configuration management system has been designed and implemented with layered managed object. It provides that integrated management of various data link layer technology. We suggest MIB(Management Information Base)/MIT(Management Information Tree) to support integrated management and distributed environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.798-801
• /
• 2010

This paper describes an efficient architecture for LDPC(Low-Density Parity Check) decoder, which supports three block lengths (648, 1,296, 1,944) of IEEE 802.11n standard. To minimize hardware complexity, the min-sum algorithm and block-serial layered structure are adopted in DFU(Decoding Function Unit) which is a main functional block in LDPC decoder. The optimized H-ROM structure for multi block lengths reduces the ROM size by 42% as compared to the conventional method. Also, pipelined memory read/write scheme for inter-layer DFU operations is proposed for an optimized operation of LDPC decoder.

• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.4_2
• /
• pp.687-697
• /
• 2022

An automated system is needed for the effectiveness of non-destructive testing. In order to utilize the radiographic testing data accumulated in the film, the types of welding defects were classified into 9 and the shape of defects were analyzed. Data was preprocessed to use deep learning with high performance in image classification, and a combination of one-stage/two-stage method and convolutional neural networks/Transformer backbone was compared to confirm a model suitable for welding defect detection. The combination of two-stage, which can learn step-by-step, and deep-layered CNN backbone, showed the best performance with mean average precision 0.868.

• International Journal of Computer Science & Network Security
• /
• v.23 no.9
• /
• pp.100-110
• /
• 2023

The Internet of Things (IoT) is the most creative and focused technology to be employed today. It increases the living conditions of both individuals and society. IoT offers the ability to recognize and incorporate physical devices across the globe through a single network by connecting different devices by using various technologies. As part of IoTs, significant questions are posed about access to computer and user privacy-related personal details. This article demonstrates the three-layer architecture composed of the sensor, routing, and implementation layer, respectively, by highlighting the security risks that can occur in various layers of an IoT architecture. The article also involves countermeasures and a convenient comparative analysis by discussing major attacks spanning from detectors to application. Furthermore, it deals with the basic protocols needed for IoT to establish a reliable connection between objects and items.