Ward Identities and High-energy Scattering Amplitudes in String Theory

High-energy limit of stringy Ward identities derived from the decoupling of two types of zero-norm states in the old covariant first quantized (OCFQ) spectrum of open bosonic string are used to check the consistency of saddle point calculations of high energy scattering amplitudes of Gross and Mende and Gross and Manes. Some inconsistencies of their saddle point calculations are found even for the string-tree scattering amplitudes of the excited string states. We discuss and calculate the missing terms of the calculation by those authors to recover the stringy Ward identities. In addition, based on the tree-level stringy Ward identities, we give the proof of a general formula, which was proposed previously, of all high energy four-point string-tree amplitudes of arbitrary particles in the string spectrum. In this formula all such scattering amplitudes are expressed in terms of those of tachyons as conjectured by Gross. The formula is extremely simple which manifestly demonstrates the universal high energy behavior of the interactions among all string states.Comment: 1 typo, to appear in Nucl. Phys.

Blast Load Input Estimation of the Medium Girder Bridgeusing Inverse Method

Innovative adaptive weighted input estimation inverse methodology for estimating theunknown time-varying blast loads on the truss structure system is presented. This method isbased on the Kalman filter and the recursive least square estimator (RLSE). The filter models thesystem dynamics in a linear set of state equations. The state equations of the truss structureare constructed using the finite element method. The input blast loads of the truss structuresystem are inverse estimated from the system responses measured at two distinct nodes. Thiswork presents an efficient weighting factor  applied in the RLSE, which is capable of providinga reasonable estimation results. The results obtained from the simulations show that the methodis effective in estimating input blast loads, so has great stability and precision.Defence Science Journal, 2008, 58(1), pp.46-56, DOI:http://dx.doi.org/10.14429/dsj.58.162

Determination of Moving Tank and Missile ImpactForces on a Bridge Structure

A method to determine the moving tank and missile impact forces on a bridge is developed. The presentmethod is an online adaptive recursive inverse algorithm, which is composed of the Kalman filter  and therecursive least square estimator (RLSE), to estimate the force inputs on the bridge structure. The state equationsof the bridge structure were constructed by using the model superposition and orthogonal technique. Byadopting this inverse method, the moving tank and missile impact force inputs acting on the bridge structuresystem can be estimated from the measured dynamic responses. Besides, this work presents an efficientweighting factor applied in the RLSE, which is capable of providing a reasonable estimation results. The resultsobtained from the simulations show that the method is effective in determining the moving tank and missileimpact forces, so that the acceptable results can be obtained.Defence Science Journal, 2008, 58(6), pp.752-761, DOI:http://dx.doi.org/10.14429/dsj.58.170

Zero-norm states and stringy symmetries

We identify spacetime symmetry charges of 26D open bosonic string theory from an infinite number of zero-norm states (ZNS) with arbitrary high spin in the old covariant first quantized string spectrum. We give various evidences to support this identification. These include massive sigma-model calculation, Witten string field theory calculation, 2D string theory calculation and, most importantly, three methods of high-energy stringy scattering amplitude calculations. The last calculations explicitly prove Gross's conjectures in 1988 on high energy symmetry of string theory.Comment: 6 pages. Talks presented by Jen-Chi Lee at XXVIII Spanish Relativity Meeting (ERE2005),"A Century of Relativity Physics",Oviedo,Spain,6-10 Sep 2005 and "4th Meeting on constrained Dynamics and Quantum Gravity",Cala Gonone,Sardinia,Italy,12-16 Sep 2005. To appear in the Journal of Physics: Conference Serie

Group Decision Making for a Fuzzy Software Quality Assessment Model to Evaluate User Satisfaction

Information techniques have brought us tremendous benefit, whereas people are increasingly depended on lots of information systems. Therefore, how to establish an assessment model to choose a better software quality suitable for end-users is an important issue. This study is to present an algorithm of the group decision makers with crisp or fuzzy weights to tackle the integrated software quality for evaluating user satisfaction using fuzzy set theory, where the grades of quality and the grade of importance of quality items are assessed by linguistic values represented by triangular fuzzy numbers. The proposed algorithm is more flexible and useful than the ones that have presented before, since the weights against decision makers are considered

THERMAL BEHAVIOR IN A MULTI-LAYER METAL THIN-FILM WITH INTERFACIAL CONTACT CONDUCTANCE BY THE PARABOLIC TWO-STEP MODEL

ABSTRACT The effect of the contact conductance on micro-scale heat transport in a multi-layered metal thin-film subjected to ultrafast pulse laser heating is investigated in this study. The interfacial contact conductance existing at the interface is included in the analysis. The parabolic two-step (PTS) model is applied to predict the electron and lattice temperature. The equations can be solved by Laplace transform and the Riemann-sum approximation. The results show that the contact conductance plays an important role in the micro-scale heat transport processes for a multi-layered metal thin-film. Hence, in order to eliminate the thermal failure of the surface layer, the thermal resistance existing at the interface should be as small as possible. INTRODUCTION Ultra-fast pulse-laser heating on the metals are widely used in thermal processing of materials, for instance, laser micromachining, laser patterning, laser processing of diamond films from carbon ion implanted copper substrates, and laser surface hardening Since high-power laser can lead to thermal damage at the front surface of a single layer film, multi-layered metal films are widely used to avoid the problem of thermal damage [3] The effects of interfacial contact conductance and the thickness of the surface layer on the temperature solution of the material are also investigated. Lee and Tsai [10] also examined the parabolic two-step model t

High-energy zero-norm states and symmetries of string theory

High-energy limit of zero-norm states (HZNS) in the old covariant first quantized (OCFQ) spectrum of the 26D open bosonic string, together with the assumption of a smooth behavior of string theory in this limit, are used to derive infinitely many linear relations among the leading high-energy, fixed angle behavior of four point functions of different string states. As a result, ratios among all high-energy scattering amplitudes of four arbitrary string states can be calculated algebraically and the leading order amplitudes can be expressed in terms of that of four tachyons as conjectured by Gross in 1988. A dual calculation can also be performed and equivalent results are obtained by taking the high-energy limit of Virasoro constraints. Finally, as a consistent sample calculation, we compute all high-energy scattering amplitudes of three tachyons and one massive state at the leading order by saddle-point approximation to justify our results.Comment: 10 pages, no figure, modifications of text and reference

Coexistence of anterior communicating artery aneurysm and tuberculum sellae meningioma

SummaryTuberculum sellae meningioma is a common intracranial tumor. However, its coexistence with an intratumoral aneurysm is rare. Here, we present the case of a 65-year-old woman with progressive vision loss caused by a tuberculum sellae meningioma coexisting with an intratumoral anterior communicating artery aneurysm. Treatment modalities for patients with this rare coexisting pathology were reviewed. When an intracranial tumor is closely related to the major intracranial vessel, preoperative magnetic resonance imaging angiography, a safe and noninvasive imaging study, is suggested for the early diagnosis of a possible coexisting aneurysm and for reducing the risk of intraoperative aneurysm rupture