企业与商事主体的关系辨析

“企业主体论”是经济学的产物，将其不加辨别地移植入商法理论体系，存在着一系列重大的理论误区与陷阱。不论从语源意义，还是从法学方法论上，企业只能是一种客体存在，是通过物质的企业组织起来的权利、法律关系及事实关系的综合统一体，并且构成商事主体的资格依托和经营目的，代表和反映着商事主体经营方面的组织举措。还商事主体以本来面目，无疑是一种人文精神的回归。     

H∞ controller synthesis for pendulum-like systems

This paper focus on a stabilization problem for a class of nonlinear systems with periodic nonlinearities, called pendulum-like systems. A notion of Lagrange stabilizability is introduced, which extends the concept of Lagrange stability to the case of controller synthesis. Based on this concept, we address the problem of designing a linear dynamic output controller which stabilizes (in the Lagrange sense) a pendulum-like system within the framework of the H_∞ control theory. Lagrange stabilizability conditions for uncertainty-free systems and systems with norm-bounded uncertainty in the linear part are derived, respectively. When these conditions are satisfied, the desired stabilization output feedback controller can be constructed via feasible solutions of a certain set of linear matrix inequalities (LMIs).     

Funkraum mit Antennentragemast; trennbare Teile eines Bauvorhabens; Verfahrensart

Beim Einbau eines Funkraumes im Dachboden und der Aufstellung eines sichtbaren Antennentragemastes handelt es sich um trennbare Teile eines Bauvorhabens. Die Errichtung eines sichtbaren Antennentragmastes ist anzeigepflichtig. Der Einbau eines Funkraumes in einem Geb?ude ist eine bewilligungspflichtige Nutzungs?nderung.     

移动WiMAX技术与商用进展

本文对WiMAX的最新标准进展及技术热点进行了介绍．对移动WiMAX商用进展进行概述，并分析了移动WiMAX产业链发展趋势．总结了移动WiMAX的优势与挑战．并对其今后在中国发展的不确定性进行了分析，主要有三个方面：中国3G许可证未发，寻找移动WiMAX的可用频率比固定WiMAX更为困难；技术上的选择可能影响中国整个电信行业的发展。     

Comparison of stability and queueing times for reader-writer queues

A reader-writer queue manages two classes of customers: readers and writers. An unlimited number of readers can be processed in parallel; writers are processed serially. Both classes arrive according to a Poisson process. Reader and writer service times are general iid random variables. There is infinite room in the queue for waiting customers.

In this paper, a reader-writer queue is considered under the following priority disciplines: strong reader preference (SRP), reader preference (RP), alternating exhaustive priority (AEP), writer preference (WP), and strong writer preference (SWP). Preemptive priority is given to readers under the SRP discipline, or to writers under the SWP discipline. Non-preemptive priority is accorded to readers with the RP discipline, or to writers with the WP discipline. For the AEP discipline, customers of a given class are served exhaustively in an alternating fashion.

For the five priority disciplines, a stability condition and first moments for the steady-state reader and writer queueing times are given. Using these analytical results, each of the five priority disciplines is seen to be optimal (among the five) in some region of the parameter space. Simulation results are also presented.     

A non-recursive method for solving the general discrete-time riccati equations related to the H∞ control problem

In this paper we propose a nonrecursive method for solving the general discrete-time algebraic Riccati equation related to the H_∞ control problem (H_∞-DARE). We have achieved this by casting the problem of solving a given H_∞-DARE to the problem of solving an auxiliary continuous-time algebraic Riccati equation associated with the H_∞ control problem (H_∞-CARE) for which the well known nonrecursive methods of solving are available. The advantages of our approach are: it reduces the computation involved in the recursive algorithms while giving much more accurate solutions, and it readily provides the properties of the general H_∞-DARE.     

Buffer sizing in an ATM switch for both ATM and STM traffics

Specific queueing models are derived in order to size the buffers of ATM switching elements in the cases of ATM or STM multiplexed traffic. Buffering is performed either at the outputs or in a central memory for ATM multiplexed traffic; for STM multiplexed traffic, buffers can also be provided at the inputs. The buffer size is chosen in order to ensure a loss probability in the switch smaller than 10^?10. It is shown that the buffer size per output in the case of central queueing is smaller than the buffer size in case of output queueing for both ATM and STM multiplexed traffics. Moreover, for STM multiplexed traffic, buffer sizes are identical for input and output queueing. Lastly, it is pointed out that buffers used for STM multiplexed traffic should be 4 to 20 times larger than the corresponding buffers for ATM multiplexed traffic.     

Adaptive motion/force tracking control of holonomic constrained mechanical systems: a unified viewpoint

This paper proposes a robust adaptive motion/force tracking controller for holonomic constrained mechanical systems with parametric uncertainties and disturbances. First, two types of well‐known holonomic systems are reformulated as a unified control model. Based on the unified control model, an adaptive scheme is then developed in the presence of pure parametric uncertainty. The proposed controller guarantees asymptotic motion and force tracking without the need of extra conditions. Next, when considering external disturbances, control gains are designed by solving a linear matrix inequality (LMI) problem to achieve prescribed robust performance criterion. Indeed, arbitrary disturbance/parametric error attenuation with respect to both motion and force errors along with control input penalty are ensured in the L₂‐gain sense. Finally, applications are carried out on a two‐link constrained robot and two planar robots transporting a common object. Numerical simulation results show the expected performances. Copyright © 2006 John Wiley & Sons, Ltd.     

Investigation of proton induced reactions on niobium at low and medium energies

Niobium is a metal with important technological applications: use as alloying element to increase strength of super alloys, as thin layer for tribological applications, as superconductive material, in high temperature engineering systems, etc. In the frame of a systematic study of activation cross-sections of charged particle induced reactions on structural materials proton induced excitation functions on Nb targets were determined with the aim of applications in accelerator and reactor technology and for thin layer activation (TLA). The charged particle activation cross-sections on this element are also important for yield calculation of medical isotope production (^88,89Zr, ^86,87,88Y) and for dose estimation in PET targetry. As niobium is a monoisotopic element it is an ideal target material to test nuclear reaction theories. We present here the experimental excitation functions of ⁹³Nb(p,x)^90,93mMo, ^92m,91m,90Nb, ^88,89Zr and ⁸⁸Y in the energy range 0-37 MeV.The results were compared with the theoretical cross-sections calculated by means of the code ALICE-IPPE, EMPIRE-3, TALYS and with the literature data. The theory reproduces the shape of the measured results well and magnitude is also acceptable.Thick target yields calculated from our fitted cross-section give reliable estimations for production of medically relevant radioisotopes and for dose estimation in accelerator technology.