Sang Il Lee

Methodology of Analyzing the Measure of Combat Effectiveness Reflecting Communication Effects in Network Centric Warfare

ABSTRACTAs a future warfare is changed to network-centric warfare (NCW), importance of research on the relation between combat effectiveness and communication effect has increased. The combat effectiveness has been analyzed using war game simulator and the communication effect has been analyzed using communication simulator. However, the relation of them has not been researched so far. In this paper, we describe a methodology of analyzing the measure of effectiveness reflecting communication effects in NCW. In the methodology, firstly, simulation interoperation environment between the war game simulator and the communication simulator is developed. Especially, we propose an interface model and interoperation interface to support the simulators for simulation interoperation. Then, we statistically analyze the output data of the simulation interoperation environment and develop a meta-model which illustrates the relation between war game and communication simulator directly. With this methodology, we can figure out the relation between the war game and communication simulator directly. Moreover, we expect that this relation effects on developing doctrines, communication operation and communication devices.

Capability-based semantic matching for dynamic resource allocation in tactical edge environment

There are technological, operational, and environmental constraints at tactical edge, which are disconnected operation, intermittent connectivity, and limited bandwidth, size, weight and power limitations, ad-hoc and mobile network, and so on. Moreover, an operational environment is highly dynamic: requirements change in response to the emerging situation, and the availability of resources needs to be updated constantly due to the factors, such as technical failures. Therefore, an efficient matching mechanism is required that considers all possible criteria to achieve a mission. In this paper, we proposed an ontology-based mission service model that consists of a mission, tasks, services, and resources, and developed a capability-based matching mechanism in tactical edge environment. In addition, we have developed a prototype that supports dynamic resource allocation during executing a mission in tactical edge.

Wireless small-world networks with beamforming

To maximize the gain of multi-hop transmissions, we have to let the number of hops as small as possible, decreasing multi-hop transmission delay. In this paper, we propose how the average number of hop counts can be reduced in wireless multi-hop networks by constructing a few long-range edges that can act as if they were highways in the networks. For this purpose, we adopt the concept of small-world phenomenon [2] and suggest two methods for giving randomness in connectivity, power control and beamforming. Based on these methods, we investigate how the network capacity can be improved by utilizing the small-world characteristics. From our numerical examples, we have found that power control with single antenna decreases not the average hop counts, but also the end-to-end throughput of the network. Power control with beamforming, however, can somewhat overcome this throughput degradation only with two antennas, where the average number of hop counts is reduced like in small-world networks.

Mission-oriented service development using capability-based semantic recommendation for the internet of things

This paper presents a mission-oriented service development environment with web-based modeling tool that enable users create workflow-based service composition. This approach utilizes the ontology-based mission service model composed of mission, task, service and resource, and task/service recommendation. During developing the mission-oriented service, capability-based semantic matching and hierarchical relationship-based filtering are used for three types of recommendation. Also, we develop a modeling environment to monitor and execute the mission service application. In experiments, we have conducted on test beds in two domains such as military environment and smart building.

IoT Platform Implementation and Service Operating Method for Private Networks

ABSTRACT Today various IoT platforms exist, but most of them only consider IPv6, without other types of network including private network. They support, therefore, the private network to use virtual private network or through the hardware gateway. To solve this limitation, we propose a IoT platform that provides IoT Services on private networks. Also we verify this platform though constructing a testbed.Keywords:Internet of Things, Proxy, IoT Platform, Smart Building, Private Network 용이한 사설망 지원을 위한 IoT 플랫폼 구현 및 서비스 운영 방법 이 경 훈 † ⋅김 두 영 †† ⋅송 세 헌 ††† ⋅이 상 일 †††† ⋅박 재 현 †††† 요 약 현재 출시된 다양한 사물인터넷(IoT) 플랫폼은 대부분 IPv6의 네트워크 환경을 고려하여 개발되었지만, 아직까지 IPv4에서 IPv6로의 전환율은 저조하다. 따라서 IPv4기반의 네트워크에서 운용되는 IoT 플랫폼은 IP부족현상을 해결하기 위해 기구축된 사설망을 지원해야 한다. 기존 IoT 플랫폼들은 전문가에 의해 가상 사설망을 이용하거나 하드웨어 스위치/AP(Access Point)를 이용하여 사설망을 지원하고 있다. 본 연구에서는 기존 IoT 플랫폼들이 사설망 환경을 지원하기 위해 필요한 전문가 활용 또는 하드웨어 도입에 따른 추가 비용 문제를 해결하고, 비전문가도 사설망 환경에서 IoT 서비스를 제공할 수 있는 IoT 플랫폼을 개발하였다. 또한 IoT 플랫폼을 테스트베드에 적용하여 IoT 플랫폼의 기능 검증을 수행하였다.키워드:사물인터넷, 프록시, IoT 플랫폼, 스마트빌딩, 사설망

Link weight optimization for routing considering link utilization in communication networks

In this paper, we study the problem that finds optimal link weights for routing in communication networks with a target utilization for each link. Since the problem is known as NP-hard, we take a heuristic approach based on the simulated annealing method. However, to make the algorithm to be more robust and converge fast, we modify the basic simulated annealing method. Numerical results show that our algorithm provides a better performance than the basic simulated annealing method.

Opportunistic subchannel scheduling for OFDMA cellular networks with scheduling at relay stations

We address an opportunistic subchannel scheduling problem in relay-based OFDMA cellular networks. In most previous works on relay-based cellular networks, immediate relaying at relay stations (RSs) was assumed, without allowing the opportunistic scheduling at RSs. Hence, each RS should transmit the received data from the base station (BS) to the corresponding mobile stations (MSs) immediately within a single time-slot and the effective data rate of the two-hop transmission (BS-RS and RS-MS links) is limited by the achievable data rate of the link with worse channel state among two links, resulting in wastes of radio resources. However, if the opportunistic scheduling is allowed at each RS, the time-varying channel state of each link can be fully exploited, and thus more efficient radio resource allocation is possible. Hence, in this paper, we consider an opportunistic subchannel scheduling at both BS and RSs. We formulate a stochastic optimization problem that aims at maximizing the average sum-rate of the relay-based network where the time-varying wireless channel is modeled as a stochastic process. By solving the problem, we develop an optimal opportunistic subchannel scheduling algorithm for both BS and RSs. Numerical results show that we can significantly improve system performance by allowing the opportunistic scheduling at RSs.

Visibility-based modelling and control for network-based robotics

We present an algorithm to model 3D workspace and to understand test scene for navigation or human computer interaction in network-based mobile robot. This was done by line-based modelling and recognition algorithm. Line-based recognition using 3D lines has been tried by many researchers however its reliability still needs improvement due to ambiguity of 3D line feature information from original images. To improve the outcome, we approach firstly to find real planes using the given 3D lines and then to implement recognition process. The methods we use are principle component analysis (PCA), plane sweep, visibility test, and iterative closest point (ICP). During the implementation, we also use 3D map information for localization. We apply this algorithm to real test scene images and to find out our result can be useful to identify doors or walls in indoor environment with better efficiency.