• Journal of Communications and Networks
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• v.8 no.1
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• pp.49-58
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• 2006

One of the first decisions that a radio network designer must take is the location of base stations and the distance between them in order to give the best coverage to a region and, possibly, to reduce deployment costs. In this paper, the authors give an insight to this matter by presenting a possible solution to a real problem: Planning the base stations layout for a universal mobile telecommunications system (UMTS) in the city of Barcelona. At the basis of this problem, there is the interdependence between coverage and capacity in a wideband-code division multiple access (W-CDMA) system, which is a new element in the planning of BS layout for mobile communications. This aspect has been first treated with an analytical study of the cell coverage range for a specific environment and service. The achieved results have been checked with the help of snapshot simulations together with a geographical information system (GIS) tool incorporated in the simulator that allows to perform analysis and to visualize results in a useful way. By using the simulator, it is also possible to study a more complex environment, that of a set of base stations providing multiple services to a large number of users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4432-4450
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• 2014

It is widely observed that in practical wireless cooperative communication systems, different links may experience different fading characteristics. In this paper, we investigate into the outage probability and channel capacity of two-way amplify-and-forward (TWAF) relaying systems operating over a mixed asymmetric Rician and Rayleigh fading scenario, with different amplification policies (AP) adopted at the relay, respectively. As TWAF relay network carries concurrent traffics towards two opposite directions, both end-to-end and overall performance metrics were considered. In detail, both uniform exact expressions and simplified asymptotic expressions for the end-to-end outage probability (OP) were presented, based on which the system overall OP was studied under the condition of the two source nodes having non-identical traffic requirements. Furthermore, exact expressions for tight lower bounds as well as high SNR approximations of channel capacity of the considered scenario were presented. For both OP and channel capacity, with different APs, effective power allocation (PA) schemes under different constraints were given to optimize the system performance. Extensive simulations were carried out to verify the analytical results and to demonstrate the impact of channel asymmetry on the system performance.

• ETRI Journal
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• v.27 no.4
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• pp.341-354
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• 2005

The adaptation of video according to the heterogeneous and dynamic resource constraints on networks and devices, as well as on user preferences, is a promising approach for universal access and consumption of video content. For optimal adaptation that satisfies the constraints while maximizing the utility that results from the adapted video, it is necessary to devise a systematic way of selecting an appropriate adaptation operation among multiple feasible choices. This paper presents a general conceptual framework that allows the formulation of various adaptations as constrained optimization problems by modeling the relations among feasible adaptation operations, constraints, and utilities. In particular, we present the feasibility of the framework by applying it to a use case of rate adaptation of MPEG-4 video with an explicit modeling of adaptation employing a combination of frame dropping and discrete cosine transform coefficient dropping, constraint, utility, and their mapping relations. Furthermore, we provide a description tool that describes the adaptation-constraint-utility relations as a functional form referred to as a utility function, which has been accepted as a part of the terminal and network quality of service tool in MPEG-21 Digital Item Adaptation (DIA).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.5
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• pp.103-108
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• 2005

In this article, it has been shown that penises devices such as illumination facilities, heating/cooling systems and security equipment can be controlled even outside premises using UPnP (Universal Plug and Play) applicable to the Internet or cellular phone services. To load UPnP protocol into each device, current manufacturers will be required to port flexible OS (Operating System), that is, Windows or Linux to these premises devices. Furthermore, prospective users want to experience a variety of specific functions based on more standardized and stable network. This study aims to provide application by implementing these functions on the Linux system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.346-348
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• 2022

A monitoring system was constructed to identify the cause of occurrence based on data on the analysis of the ignition factors of fermentation heat generated from loading waste. Universal Middleware was used to provide a real-time run-time environment for the configuration and speed of scenarios for each type of fire early warning. It is necessary to dynamically recognize the loading height and pressure of the loading waste, the drying of wood, batteries, and plastic waste, which are representative compositional wastes, and the carbonization changes on the surface. Therefore, this IoT situation recognition platform for analyzing low-temperature-fired fire possibility data was dynamically configured and presented.

• IMMUNE NETWORK
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• v.23 no.4
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• pp.32.1-32.15
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• 2023

Most influenza vaccines currently in use target the highly variable hemagglutinin protein to induce neutralizing antibodies and therefore require yearly reformulation. T cell-based universal influenza vaccines focus on eliciting broadly cross-reactive T-cell responses, especially the tissue-resident memory T cell (T_RM) population in the respiratory tract, providing superior protection to circulating memory T cells. This study demonstrated that intramuscular (i.m.) administration of the adenovirus-based vaccine expressing influenza virus nucleoprotein (rAd/NP) elicited weak CD8 T_RM responses in the lungs and airways, and yielded poor protection against lethal influenza virus challenge. However, a novel "prime-and-deploy" strategy that combines i.m. vaccination of rAd/NP with subsequent intranasal administration of an empty adenovector induced strong NP-specific CD8⁺ T_RM cells and provided complete protection against influenza virus challenge. Overall, our results demonstrate that this "prime-and-deploy" vaccination strategy is potentially applicable to the development of universal influenza vaccines.

• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.57-66
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• 2009

Zigbee is a universal communication standard used in USN and is utilized in various applications. Zigbee protocol provides an address within a single PAN network, and at this time, it uses DAA. This is a method that divides a 16-bit address area into blocks with a fixed size according to the depth to assign one to each node. However, this method is limited because it has to assign addresses in 16 bits. As the depth increases, the number of nodes also increases exponentially to the maximal number of routers provided to each depth. Therefore, it is difficult to construct a huge network with numerous routers and large depth as in the places which are wide or have many shadow areas. Besides, since all the operations are performed in a single PAN network, it is hard to make several PANs into a single network. This article suggests new addressing and routing methods that can construct several PAN networks into a single network and combine broad area with less limitation in the number of routers and depth by extending the Zigbee-based network. Moreover, this paper has tested its performance and has verified its usability through substantive tests.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.695-698
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• 2007

The control of electrical appliances residing in the home network can be accomplished via Internet with the UPnP expansion without modifying an existing UPnP. In this paper, we propose the Internet Gateway that consists of an UPnP IGD(Internet Gateway Device) DCP(Device Control Protocol) and an UPnP Bridge as a system to control electrical appliances of home network. UPnP IGD DCP is to enable the configurable initiation and sharing of Internet connections as well as assuring advanced connection-management features and management of host configuration service. It also supports transparent Internet access by non-UPnP-certified devices. UPnP Bridge searches for local home network devices by sending control messages, while control point of UPnP Bridge looks up devices of interest on the Internet, subsequently furnishing the inter-networking controlling among devices which belong to different home network systems. With our approach, devices on one home network can control home electrical appliances on the other hone network via Internet through IGD DCP with control commands of UPnP.

• Geomechanics and Engineering
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• v.22 no.2
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• pp.133-142
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• 2020

The evolution of the mining-induced fracture network formed during longwall top coal caving (LTCC) has a great influence on the gas drainage, roof control, top coal recovery ratio and engineering safety of aquifers. To reveal the evolution of the mining-induced stress and fracture network formed during LTCC, the fracture network in front of the working face was observed by borehole video experiments. A discrete element model was established by the universal discrete element code (UDEC) to explore the local stress distribution. The regression relationship between the fractal dimension of the fracture network and mining stress was established. The results revealed the following: (1) The mining disturbance had the most severe impact on the borehole depth range between approximately 10 m and 25 m. (2) The distribution of fractures was related to the lithology and its integrity. The coal seam was mainly microfractures, which formed a complex fracture network. The hard rock stratum was mainly included longitudinal cracks and separated fissures. (3) Through a numerical simulation, the stress distribution in front of the mining face and the development of the fracturing of the overlying rock were obtained. There was a quadratic relationship between the fractal dimension of the fractures and the mining stress. The results obtained herein will provide a reference for engineering projects under similar geological conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1159-1166
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• 2014

In this paper, a resource management scheme for enhancing the network connectivity and reliability in wireless USB system is proposed. Wireless USB protocol is suitable for the application that supports the real-time multimedia service in Ship Area Network since it supports high speed data transfer. However, the device's mobility is caused the dramatic change of link state and network topology, and is occurred the degradation of network performance. Therefore, a resource management scheme for wireless USB system is proposed in this paper. The proposed technique can intelligently treat the change of link state, and solve the degradation of network performance. The simulation results show that proposed protocol can enhance the throughput and delay performance by selecting relay device with better link state.