Hit Point Research Articles

Countermeasure effectiveness against a man-portable air-defense system containing a two-color spinscan infrared seeker

Man-portable air-defense (MANPAD) systems have developed sophisticated counter-countermeasures (CCM) to try and defeat any expendable countermeasure that is deployed by an aircraft. One of these is a seeker that is able to detect in two different parts of the electromagnetic spectrum. Termed two-color, the seeker can compare the emissions from the target and a countermeasure in different wavebands and reject the countermeasure. In this paper we describe the modeling process of a two-color infrared seeker using COUNTERSIM, a missile engagement and countermeasure software simulation tool. First, the simulations model a MANPAD with a two-color CCM which is fired against a fast jet model and a transport aircraft model releasing reactive countermeasures. This is then compared to when the aircraft releases countermeasures throughout an engagement up to the hit point to investigate the optimum flare firing time. The results show that the release time of expendable decoys as a countermeasure against a MANPAD with a two-color CCM is critical.

이종 온라인 게임 서버 간의 게임 캐릭터 이주를 위한 웹 서비스 시스템 설계 및 구현

온라인 게임에서 게임 플레이어를 대신하는 게임 캐릭터는 동일한 게임 내에서만 존재하며, 다른 온라인 게임으로 이주하는 것이 매우 어렵다. 또한 게임 플레이어는 자신의 게임 캐릭터의 성장에 많은 시간과 노력을 빼앗기고 있으며, 최근에는 이것이 많은 사회적 부작용을 낳고 있다. 따라서 본 논문은 이러한 문제점을 해결하기 위해서 기존 연구를 기반으로 이종 온라인 게임 서버 간의 게임 캐릭터 이주를 위한 웹 서비스 시스템을 설계 및 구현하였다. 그리고 제안된 시스템은 실험을 통하여 게임 캐릭터 이주 요소 중에서 4가지 능력치 (금전, HP:Hit Point, MP:Mana Point, 레벨)를 중심으로 검증하였다. In the online game, a game character to replace game player exists within the same game and it is very difficult to migrate to another on-line games. Also, players have taken a lot of time and effort in the character's growth. In recent years, it has raised many social side effects. Therefore, in order to solve these problems, this paper was implemented web services system based on previous studies for the migration of game character between different-type on-line game severs, and the proposed system verified through the experiment focused on 4 capability numerical value (money, HP:Hit Point, MP:Mana Point, level) between migration element of game character.

Simulating pre-emptive countermeasures of varying performance against a Man-Portable Air-Defence (MANPAD) system with a track angle bias counter-countermeasure (CCM)

Military aircraft face a serious threat from early generation Man-Portable Air-Defence (MANPAD) systems. Robust countermeasures have to be used to counteract this threat. Most commonly these are used after the threat has been launched and detected. However, a MANPAD may or may not include counter-countermeasures (CCMs) that are designed to defeat reactively fired decoys. In this paper we investigated the effect of pre-emptive countermeasures on different MANPAD models. This is achieved through the use of CounterSim, a missile engagement and countermeasure simulation software tool, which has the ability to model the full pre-launch phase of an engagement between a MANPAD and an aircraft. Three MANPAD models are developed with one infrared (IR) seeker containing a track angle bias CCM capability and two different CCM triggers. The first simulations look at pre-emptive flare deployment for the full operational envelope of an early generation MANPAD. Then, simulations compare reactive with pre-emptive countermeasure deployment by firing flares throughout an engagement up until the hit point. Finally, different flare types are looked at with reduced burn time and intensity.

Cache-oblivious ray reordering

We present a cache-oblivious ray reordering method for ray tracing. Many global illumination methods such as path tracing and photon mapping use ray tracing and generate lots of rays to simulate various realistic visual effects. However, these rays tend to be very incoherent and show lower cache utilizations during ray tracing of models. In order to address this problem and improve the ray coherence, we propose a novel Hit Point Heuristic (HPH) to compute a coherent ordering of rays. The HPH uses the hit points between rays and the scene as a ray reordering measure. We reorder rays by using a space-filling curve based on their hit points. Since a hit point of a ray is available only after performing the ray intersection test with the scene, we compute an approximate hit point for the ray by performing an intersection test between the ray and simplified representations of the original models. Our method is a highly modular approach, since our reordering method is decoupled from other components of common ray tracing systems. We apply our method to photon mapping and path tracing and achieve more than an order of magnitude performance improvement for massive models that cannot fit into main memory, compared to rendering without reordering rays. Also, our method shows a performance improvement even for ray tracing small models that can fit into main memory. This performance improvement for small and massive models is caused by reducing cache misses occurring between different memory levels including the L1/L2 caches, main memory, and disk. This result demonstrates the cache-oblivious nature of our method, which works for various kinds of cache parameters. Because of the cache-obliviousness and the high modularity, our method can be widely applied to many existing ray tracing systems and show performance improvements with various models and machines that have different cache parameters.

The CMS muon system alignment

The alignment of the muon system of CMS is performed using different techniques: photogrammetry measurements, optical alignment and alignment with tracks. For track-based alignment, several methods are employed, ranging from a hit and impact point (HIP) algorithm and a procedure exploiting chamber overlaps to a global fit method based on the Millepede approach. For start-up alignment as long as available integrated luminosity is still significantly limiting the size of the muon sample from collisions, cosmic muon and beam halo signatures play a very strong role. During the last commissioning runs in 2008 the first aligned geometries have been produced and validated with data. The CMS offline computing infrastructure has been used in order to perform improved reconstructions. We present the computational aspects related to the calculation of alignment constants at the CERN Analysis Facility (CAF), the production and population of databases and the validation and performance in the official reconstruction. Also the integration of track-based and other sources of alignment is discussed.

Effect of water cooling conditions on splash break occurance during aluminum DC casting

The cooling water used in vertical aluminum DC casting is generally induced to just under the mold to prevent molten aluminum break out. However, the cooling water leaks into the air gap between the mold and the surface of ingot, so water splashes over the top of the molten aluminum, resulting in uneven cooling. But the quantitative survey on the splash break behavior and the change in the cooling condition has not been conducted. Hence, to quantify the splash break condition and the cooling capability, we have made the “Cooling water simulator” capable of freely controlling the potential splash causing factors such as temperature of cooling water, water flow rate, air gap amount, and angle of the water flow, reproducing the splash, and measuring the heat transfer value. The experimental result reveals that the temperature of cooling water is not a factor highly influencing on heat flux and splash, but the splash behavior highly depends on three factors which are the water flow rate, the angle of water flow, and the distance between the cooling water hit point level and the cooling water exit level. And that the heat flux also increases when splash occurs. In addition, the splash break parameter was drawn based on the above three factors, and the correlation between splash break parameter and heat flux was clarified. Use of splash break parameter enables setting of the casting condition where the maximum heat flux is obtained while preventing splash.

Comparative Experiment of Whaling Grenades in the Japanese Whale Research Program under Special Permit(JARPA and JARPN)

The Japanese Whale Research Program under Special Permit in the Antarctic(JARPA) and in the Northwest Pacific Ocean (JARPN) has been conducted by the Institute of Cetacean Research(ICR). The lethal component of the JARPA and JARPN was an explosive harpoon used as the primary method of killing whales. In order to improve the method of whale killing, ICR and Kyodo Senpaku made improvements to the explosive harpoon. The newly developed Norwegian grenade and the improved Japanese grenade were compared to the traditional Japanese grenade. Trial firing using cubic target objects and practical experiments were conducted from 2000 to 2004. The new Norwegian grenade and the improved Japanese grenade decreased the time to death(TTD; the time from the first harpoon strike to death of the whale) and increased the instantaneous death rate(IDR) significantly compared to the traditional Japanese grenade. Both the improved Japanese and new Norwegian grenades have common features of low rate of misfire and short explosive distance (the distance from a hit point of the harpoon to point of the grenade explosion), which increased a rate of the explosion of the grenade inside the whale's body. Comparing the two types of grenades, the Norwegian grenade had a higher IDR for smaller whales. It was also easy to handle and load because of its integrated structure. The improved Japanese grenade had the shortest TTD and the lowest rate of misfire. As there is not much difference in actual performance between the two, the lower price of the Japanese grenade may be an important factor in selecting future whaling devices.

Application of piezoelectric and seismoelectrokinetic phenomena in exploration geophysics: Review of Russian and Israeli experiences

Systematic research of piezoelectric and seismoelectrokinetic phenomena in the context of exploration geophysics began in the former Soviet Union in the mid-1950s. These phenomena are manifested by electrical and electromagnetic (EM) processes that occur in rocks under the influence of elastic oscillations triggered by shots or mechanical impacts (hits). This paper presents a classification of piezoelectric and seismoelectrokinetic phenomena, which is based on the analysis of abundant theoretical, laboratory, and field data accumulated mainly by Soviet, Russian, and Israeli researchers. This classification divides the above phenomena into the following types: (1) the seismoelectrokinetic (electrokinetic) phenomenon E, which occurs in poly-phase media because of the mutual displacement of the solid and liquid phases; (2) the piezoelectric phenomenon, which occurs in rocks that contain piezoactive minerals; (3) the shot-triggered phenomenon, observed in rocks in the vicinity of a shotpoint or hit point; (4) the seismoelectric phenomenon I, manifested by the change of the electric current passing through rock; and (5) high-frequency impulse EM radiation, generated by massive base-metal bodies. This paper describes these five phenomena in detail — their nature, manifestation patterns, and registration techniques. Because the manifestation patterns of the phenomena differ in various types of rock, the phenomena can be used as a basis for geophysical exploration techniques. The piezoelectric method is an example of a successful application of piezoelectric and seismoelectrokinetic phenomena in exploration geophysics. This method was developed in the former Soviet Union, and it has been applied successfully in mineral exploration and research in Russia and, recently, in the West. The method uses a new geophysical parameter: piezoelectric activity of rocks, ores, and minerals. It enables direct exploration for pegmatite, apatite-nepheline, sphalerite, and ore-quartz deposits of gold, tin, tungsten, molybdenum, zinc, crystal, and other raw materials. This method also differentiates rocks such as bauxites and kimberlites from host rocks by their electrokinetic properties.

The ESCI-N Project after a decade: A síntesis of the results and open questions

A synthesis of the results and conclusions from the data corresponding to the ESCI-N project is presented. The ESCI-N project developed in the early 90’s providing the first set of deep reflection and refraction data for the Cantabrian Mountains and adjacent areas. The discovery of a crustal root beneath the highest picks of the Cordillera marked a hit point on the studies and the relationship between the Cantabrian Cordillera and the Pyrenees became clear after the ESCI-N project. The study and interpretation of these data produced important findings and new constraints greatly improving the geodynamical and evolutional models of the area.

A novel approach for determining the trajectory and speed of a supersonicobject

An experimental set-up is presented for tracking the trajectory of a supersonicobject using minimal resources. The proposed set-up, based on the use of low-costpressure transducers, a general-purpose conditioning system and off-the-shelfinstrumentation, is capable of determining the bullet trajectory, speed and hitpoint in open air use. The methodology is based on the post-processing ofshock wave information gathered by means of three spaced sensor clusters,each one comprising three pressure transducers. The pressure sensors areused to detect the times of arrival of the shock wave generated by thebullet; on the basis of geometrical considerations, from the six time delaysmeasured by means of the nine pressure sensors, the bullet direction and itsspeed are calculated. The novel contribution of the methodology describedhere, with respect to similar methods described in the literature, is thepost-processing method used. The metrological performance of the realizedexperimental set-up was calculated by means of a priori analysis to theoreticallydetermine the uncertainty maps as a function of bullet direction, after thegeometry of the clusters, their relative positions and the time resolution werechosen. The theoretical analysis was then verified with field tests in amarksmanship training range with series of straight shots hitting the targetplane from different positions at a distance of about 100 m, with bothperpendicular and inclined shots. The results obtained with the shotsperpendicular to target plate are: the error in hit points is always less than65 mm while the error associated in angle values lies in the range from−0.017 to 0.010 rad(from −1.0°to 0.6°).The worst results obtained with inclined shots, i.e. those not perpendicular to the targetplane, are: hit point error always less than 196 mm and range of variation of error angle of−0.017 and 0.038rad (−1.0°and 6.8°).Overall examination of the theoretical and experimental results indicates thecritical strengths of the method, namely accounting for environmental parameterfluctuations and accuracy in the evaluation of relative positions among theclusters.

Reconstruction of Cherenkov rings in imaging detectors

A simulation and reconstruction method is presented which enables particle identification in a multihit environment with a RICH detector even in the case where the particle hit point on the detector is not precisely determined. The method is demonstrated for the configuration of the NA35 experiment.

Scaling of Edge Magnetic Fluctuations In DIII-D L-Mode

Magnetic fluctuations at the divertor hit point were investigated during the L-mode near L-H transitions in DIII-D divertor discharges. These fluctuations show broad-band frequency spectra (15∼35 kHz) with toroidal coherency (0.4∼0.8) and rotate in the electron diamagnetic drift direction. The amplitude and the peak frequency follow different scalings. The parameter dependence of the amplitude is compared with the prediction of the microtearing and drift ballooning modes. Both modes are expected to be suppressed with increasing edge electron temperature gradient in the H-mode. The parameter scalings are more consistent with the prediction of drift ballooning modes than they are with the microtearing modes. The scaling of the frequency suggests that the peak frequency is the electron diamagnetic drift frequency for n=1 and m>5.