The initial trajectory of a spheroid configuration bobbin for precision guidance has been investigated by analyzing its aerodynamic load and six-degree-of-freedom motion. The effects of changes in the spheroidal head configuration, flow angle and lateral center-of-gravity offset are numerically studied using the commercial software "FLUENT". A wind tunnel test is also conducted to validate the numerical scheme and to examine effect of the Reynolds number on the flow around the bobbin. It is shown that the size of the separation bubble formed on the surface decreases significantly when the Reynolds number is varied between 110,000 and 140,000. At a zero flow angle, an oblate spheroidal head shows relatively moderate rotation while a prolate spheroidal head shows rapid rotation. The bobbin with a spherical head shape has little effect on the flow direction; however, the oblate bobbin is sensitive to the flow angle. The roll motion of the bobbin is greatly influenced by the lateral center-of-gravity offset and maximum dispersion is observed at half of the radius.

A simulator is proposed in this paper for predicting the RF signal level after propagating over sea and land surfaces. Various sea and land types and transmit/receive antenna patterns, as well as the locus of the transmit antenna, are considered for this simulator. At first, microwave reflection characteristics of various sea surfaces have been computed, based on an empirical formula which is developed in this study for the relation between the sea surface roughness and wind speed. Then, microwave reflections from land surfaces such as forests, agricultural areas, and bare surfaces, are computed using the first-order vector radiative transfer theory. Finally, the signal paths over sea and land surfaces are found using the ray tracing technique and the digital elevation model, and the signal level received by a receiving antenna is computed by the using the reflection coefficients of sea and land surfaces and the signal paths.

Object Generator is a software to provide simulation object data(aircraft, ship, submarine, missile, torpedo) for sumulators in LBTS(Land Based Test System). but there is a burden to the system, because Object generator needs to send many object's data, display objects in a tactical screen, show object's information in a list in 1 second. This paper suggests a parallel software structure taking a few factors(deadlock, dependency) into consideration. At last, the paper shows the performance of the parallel structure's software compared with the former structure's software.

In this paper, we propose new data association method called the Highest Probability Data Association(HPDA) using a Signal Amplitude information ordering method applied to active sonar tracking and track initiation in cluttered environment. The performance of HPDA is tested in a series of Monte Carlo simulations runs and is compared with the existing Probabilistic Data Association with Amplitude Information(PDA-AI) for active sonar tracking in clutter. The proposed HPDA algorithm is also applied to automatic track initiation in clutter and its performance is compared with the existing IPDA-AI algorithm.

Navy surface vessels require pier services such as emergency repair, oil supply, arm loading/unloading, craning, standby readiness, normal repair, gun arrangement, ammunition loading, and food loading during the period in port. The purpose of this study is to establish efficient berth allocation plan for navy surface vessels in home port under the limited resources of piers and equipments. This study suggests Mixed Integer Programming model for berth allocation problem, considering precedence relationships among services and the uncertainty of the arrival and departure for each vessel. For an effective analysis, the model is implemented by ILOG OPL(Optimization Programming Language) Studio 6.0 and ILOG CPLEX 11.1., which shows a reasonable result.

In next war, it will be expected that some requirement such as information acquisition, battlefield surveillance and control, increased power projection, precision attack by guided missile and electronic warfare may have special importance. The use of robot weapon system by Airforce will make up for some weak points of man based weapon system that Airforce currently has. And Airforce man/robot combined air vehicle weapon system can extend military operational theater and give its flexibility in next war where power, mobility and information should be all-in-one for military purpose.

It happened fractures on special bolt which supported main landing gear actuator up-lock rod of aircraft. Cracks were initiated mainly from the center hole and the external thread of the special bolt. To find out failure root causes, metallographic, fractographic analyses as well as test work were carried out. From the fractographic study by SEM work, fracture occurred by a brittle intergranular type failure. The fracture could be occurred primarily by solid-metal-induced embrittlement due to cadmium embrittler penetrated into the flaw existed after machining work for center hole and thread on the bolt during baking treatment processing to eliminate hydrogen. For its successful application, cadmium EP bolts require proper and adequate baking treatment after electroplating, and make no more drilled center hole on the bolt to prevent same failure.

In this paper we propose a design method of X band frequency hopping synthesizer in terms of phase noise and settling time with DDS driven PLL architecture, which has the advantages of high frequency resolution, fast settling time and small size. In addition, a noble method is proposed to remove the synthesizer output spurious signals due to superposition effect of DDS. The spurious signal which depend on its normalized frequency of DDS, can be dominant if they occur within the PLL loop bandwidth. We verify that the sources of that spurious signals are quasi-amplitude modulation and superposition effect, and suggest that such signals can be eliminated by intentionally creating frequency errors in the developed synthesizer.

This paper on the Research of Naval Electronic Warfare System HILS(Hardware In the Loop System) describes the EW engagement HILS construction method for evaluation of the operational concept analysis on active RF Decoy in staying in the air and the deceit ability to anti-ship missile seeker. We obtain the EW M&S technology of EW engagement HILS and EW efficiency analysis from this project. This Naval Electronic Warfare System HILS technology will support Active Decoy Development Project and any other HILS of EW weapon in KOREA ARMY/NAVY/AIR FORCE.

GPS spoofing is an intentional interference which uses the mimic GPS signals to fake the receivers. The generic GPS receiver is hard to recognize the spoofing signal because the spoofer generates the fake signals as close as possible to the GPS signal. So the spoofer can do critical damage to public operations. This paper introduces a basic concept of spoofing and analyzes the effect of the spoofing signal to the GPS receiver. Also for stand-alone GPS receivers, two anti-spoofing methods are implemented : RAIM based method and the SQM based method. To evaluate the performance of anti-spoofing method, the software based spoofing signal generator and GPS signal generator are implemented. The performance of the anti-spoofing methods obtained using the output of the software based GPS receiver shows that SQM based method is more effective when multiple spoofing signals exist.

Requirements management is one of the most essential activities of systems engineering in developing successful weapon systems. Particularly it is very important to consistently manage the traceability among the user requirements, the system requirements, the development specifications and the testing plans throughout the entire life cycle of the weapon system. However, the most part of requirements-related activities has centered around the functional and performance requirements but the integrated logistics support(ILS) requirement has not properly been managed. In this regard, a special attention is needed to develop and manage the ILS requirements. To do so, the ANSI/EIA-632 standard can be referred as a starting point since the ILS requirements of the weapon system under development are specified by the enabling products whereas the functional and performance requirements are covered by the end product requirements. Specifically, we first review and model several cases of previous weapon systems development, which reveals the problem of interest. Then, under the framework of ANSI/EIA-632, we study a hierarchical model for effectively managing ILS requirements by analyzing the features of ILS requirements. Finally, the value of the proposed model is discussed through the case study of electronic warfare equipment.

This paper proposes a novel appoach which can assess the system technical maturity for use in Defense R&D Program reviews. As the weapon systems become more complicated, the success and effectiveness of R&D outcome heavily depend on the application and tailoring of systems engineering process and methods. It is a difficult task to assess the system readiness level(SRL) of the system being developed. A system-focused approach for managing weapon systems development and making effective and efficient decisions during the development lifecycle is critical to ensure the success of the program. The proposed weighted average SRL can facilitate the system technical maturity assessment without expending heavy work load.

Exploiting models and simulations are encouraged among the defense acquisition society, as now enforced by the Defense Aquisition Program Administration's regulations. They are useful and, sometimes, inevitable especially in an earlier phase of system development. Computer-simulation-based experimentation technique for the system operational performance analysis for a torpedo defense system is introduced in this paper. Problem definition for the torpedo defense system analysis and engineering efforts for models and simulations development are presented here, including defining measures of performance and effectiveness for the torpedo defense system, conceptual modeling for torpedo engagement and defense simulation, design of experimentation, design of simulator and experimentor, and hardware and software implementation of an analysis support tool - a system operations demonstration and experimentation simulator.

It is not easy job to find a underwater target using sonar system in the ASW operations. Many researchers have tried to solve anti-submarine search problem aiming to maximize the probability of detection under limited searching conditions. The classical 'Search Theory' deals with search allocation problem and search path problem. In both problems, the main issue is to prioritize the searching cells in a searching area. The number of possible searching path that is combination of the consecutive searching cells increases rapidly by exponential function in the case that the number of searching cells or searchers increases. The more searching path we consider, the longer time we calculate. In this study, an effective algorithm that can maximize the probability of detection in shorter computation time is presented. We show the presented algorithm is quicker method than previous algorithms to solve search problem through the comparison of the CPU computation time.

The management systems of defense projects need to be well-maintained because of huge cost and long-terms of acquisition & operation in conducting defense acquisition. In this paper, we use a structural equation model(SEM) to develop an project management index(PMI) for effective defense project. The concept of a customer satisfaction index is used to assess the PMI for strategic improvement plans for various characteristics of project management. It is expected that our model can be used to evaluate and improve the project management capability of defense acquisition.

We examine interoperability for integrated training simulation of a mechanized infantry battalion that uses a war game model of Korean army, Combat 21, and virtual simulators of K1 tanks. We discuss issues and problems for integrated simulation of the virtual and constructive models, including differences between the model scopes, model resolutions, engagement algorithms, and data consistency and training audiences of the war game model and virtual simulators. From these, we identify interoperability requirements. We propose ways of resolving the problems using a model converter.

An environment in which the software is operated become more complex and changed dynamically. Such software requires the ability to adapt in accordance with operating environments, by monitoring the changes of user requirements and operating environments. Especially, the mobile device used in military operation requires more dynamical adaptation than the mobile device in normal environment. In this paper, we propose MOSAIC architecture based on Self-Adaptive Software suitable for military mobile device and verify the results. The proposed architecture consists of context manager, evaluation manager and adaptation manager. We simulate the MOSAIC architecture by modelling PRE(Position Reporting Equipment) used in the army and verify four types of operational mode and dynamical reconfiguration of user interface.

As CAS, X-ATK, and INT models considered as the most typical Air-to-Ground operation models in ROKAF are mainly designed as the voice-centered system between aircraft and ground control facilities, it is critical to newly develop the Link-16 based model for the ROK-US combined operation between F-15K, AWACS, M-SAM, and KDX-III equipped with Link-16. Former studies had been limited to the CAS operation, and they had mainly focused on reducing the voice transmission time to exchange the information between each mission step with maintaining existing operation steps. Therefore, this paper makes up the weak point in former studies, thereby designing new Air-to-Ground operation model for CAS, X-ATK, INT mission using Enterprise Architecture OV6c, which enables both aircraft and ground control facilities or between aircraft to obtain the real-time information on the location, identification, armament and the real-time image data through the broadcasting function. Based on the analysis of new operation model, we come to a conclusion that by simultaneously exchanging the information on mission between nodes concerned through the broadcasting function of Link-16. It is possible to cut down superfluous steps among the mission steps, and to reduce the mission time. It is clear that it gives rise to improve the battle efficiency and the decision-making tempo as well as the battlefield situational awareness.

A research for the optimal design of microwave absorbing material featuring for the broadband has been conducted to apply to warship. A multilayered structure was suggested using wave absorbing layers and resistance layer to perform high performance in broadband frequencies. For the optimization of the wave absorbing characteristics, the thickness and permittivities of the absorbing layers as well as the surface resistance of the resistant layer were determined using genetic algorithm. The data base of permittivities related to the density of the dielectric materials and loss materials was obtained by the experiments for the dielectric constants of the absorbing layers, furthermore, the results were numerically expressed and used for the optimization.

Recently, the role of Ubiquitous Sensor Network(USN) has been considered to be essential for supporting the near future Network Centric Warfare(NCW) and Tactical Information Communication Network(TICN). In this paper, we explore a set of data storage methods(external storage, local storage and data storage) and query processing methods in WSN. In particular, we focus on analyzing a novel data structure for supporting the local storage method, named the partial ordered tree(POT). The main idea behind POT is that sensor readings are usually correlated with the physical spatial domain. With the help of POT, only a small portion of sensor nodes participate in query processing tasks, and thus network lifetime is greatly increased. Through a series of simulation experiments, we demonstrate that the POT based local storage method clearly outperforms the existing data storage methods in terms of the energy-efficiency, which directly affects the network lifetime, for processing exact match queries, range queries and top-k queries.

This paper considers the problem of time difference-of-arrival(TDOA) source localization when the TDOA and angle of arrival(AOA) measurements from an airborne emitter source are subject to ground-platform sensor position. The optimization of sensors' position is a challenging problem and a solution with good localization accuracy has yet to be found. This paper proposes an estimator that can achieve these purposes and provides optimized sensor position for good localization accuracy using the proposed estimator. The developed algorithm and sensor position are then examined under the special case of a single airborne source. The theoretical developments are supported by simulations.

This paper presents a vision-based robust off-road terrain classification method against environmental variation. As a supervised classification algorithm, we applied a neural network classifier using wavelet features extracted from wavelet transform of an image. In order to get over an effect of overall image feature variation, we adopted environment sensors and gathered the training parameters database according to environmental conditions. The robust terrain classification algorithm against environmental variation was implemented by choosing an optimal parameter using environmental information. The proposed algorithm was embedded on a processor board under the VxWorks real-time operating system. The processor board is containing four 1GHz 7448 PowerPC CPUs. In order to implement an optimal software architecture on which a distributed parallel processing is possible, we measured and analyzed the data delivery time between the CPUs. And the performance of the present algorithm was verified, comparing classification results using the real off-road images acquired under various environmental conditions in conformity with applied classifiers and features. Experiments show the robustness of the classification results on any environmental condition.

ADAS is the air defense control system performing air surveillance and identification of ROK and near air. This system is self-developed by Air Force, currently operated successfully as the alternative system of MCRC. ADAS processes converting and combining transferred the real time radar data detected by radars. additionally, it displays significant radar data as producing in tracks. Then, it uses the message queue for IPC(Inter Process Communication). the various tactical data processed in the server is ultimately send to the network management process through the message queue for transmitting to the weapon director console. the weapon director receives this transmitted tactical data through the console to execute air defense operations. However, there is a problem that data packet is delayed or lost since the weapon Director does not receive as the amount of tactical data from the server overflowed with air tracks and missions increased. This paper improved the algorism to display and transmit the various tactical data processed from ADAS server to numbers of the weapon director console in the real time without any delay or lost. Improved the algorism, established at exercise, the development server in the real operation network and the weapon director console, is proved by comparing the number of sending tactical data packets in the server and receiving packets in the weapon director.

A modern artillery use a FMCW Proximity Fuze for effectively target destruction. FMCW Proximity Fuze can be deceived by Jamming Technique because it uses RF for distance estimation. FMCW Proximity Fuze algorithm is similar to FMCW radar's, but normal Jamming Tech. like Noise and Mulitone is useless. Most Shots with FMCW Proximity Fuze have a additional mechanical fuze against RF Jamming. Shots explode by mechanical fuze when Proximity Fuse is Jammed. However, distance Deception is available because shots can not distinguish between deception jamming signal and ground reflected signal. For making Distance Deception Jamming, FMCW signal tracking is demanded. In this paper, we propose a FMCW tracking method and develop the Jammer to show Jamming signal.

The local area weather information is very important element to estimate where the air-pollutant will flow. But the existing NBC hazard prediction model does not consider the local area weather information. So, in this paper, we present SN-HPM that uses the local area wether information to perform more accurate and reliable estimate, and embody it to program.

War field differs from conventional military education and training environments. Warfighter may confront frequently unexpected physical and psychological stimulation. Cumulative psychological stress and physical fatigue can be causes of mood distortion, declined alertness, and decreased combat capability in warfighters. Countermeasures of combat stress and fatigue is very important for keeping combat capability and saving of life. Here in, the countermeasures of combat stress and fatigue have reviewed, and limitation and the direction of research and development of countermeasures of combat stress and fatigue are proposed.

A numerical analysis for the space frame structure under ballistic and blast loads was performed using LS-DYNA, a commercial code. The space frame structure was developed to be adapted to the ground vehicle in the future and it was designed to build with Al7039 frames and lightweight multi-layered panels for the purpose of weight reduction and shock mitigation. The analyses have done for side impacts by a cylindrical projectile and Comp. C-4 explosive representing major threats to the vehicle. The deformed shape of the panel section and stresses as well as accelerations of the frames calculated from LS-DYNA were compared to the test results to validate the analysis model. The internal energies for panels and frames from LS-DYNA were also compared to each other to discern their role in absorbing the ballistic and blast impact.

The present study investigated the swimming pattern and appendage postures of a copepod species, Calanus sinicus, which prevails in the south-east sea of the Korean peninsula, by employing a digital holographic particle tracking velocimetry(PTV) technique. The results showed that the copepod Calanus sinicus had various swimming patterns such as hover, hop, sink, cruise, and downward cruise. Most frequent pattern was the 'hop and sink'. The average swimming speeds ranged from 1.1 to 45.7 body-lengths/s, and the corresponding flow Reynolds number ranged from $10^0$ to $10^2$.