Some improved two-stage shrinkage testimators for the mean of normal distribution

In this paper, we introduced some two-stage shrinkage testimators (TSST) for the mean µ when a prior estimate µ0 of the mean µ is available from the past, by considering a feasible form of the shrinkage weight function which is used in both of the estimation stages with different quantities. The expressions for the bias, mean squared error, expected sample size and relative efficiency for the both cases when o2 known or unknown, are derived and studied. The discussion regarding the usefulness of these testimators under different situations is provided as conclusions from various numerical tables obtained from simulation results

Some improved two-stage shrinkage testimators for the mean of normal distribution

In this paper, we introduced some two-stage shrinkage testimators (TSST) for the mean μ when a prior estimate μ0 of the mean μ is available from the past, by considering a feasible form of the shrinkage weight function which is used in both of the estimation stages with different quantities. The expressions for the bias, mean squared error, expected sample size and relative efficiency for the both cases when 2 known or unknown, are derived and studied. The discussion regarding the usefulness of these testimators under different situations is provided as conclusions from various numerical tables obtained from simulation results.Peer Reviewe

Merger and acquisition laws in UK, UAE and Qatar: Transferring rights and obligations

This thesis was submitted for the degree of Doctor of Law and awarded by Brunel University.Across six Chapters, this thesis examines the legal effects of mergers and acquisitions (M&As) on the employees, Board of Directors and shareholders of companies with the objective of gaining in-depth understanding of this area. The thesis then develops legal and practical solutions for the problems and negative effects associated with M&As, specifically regarding employees, Boards of Directors and shareholder companies involved in such operations. This research determines to answer the following question: How do mergers and acquisitions (M&As) affect employees, management and shareholders rights and obligations? And what the legal basis for transferring their rights and liabilities between companies involved in M&As? Despite the importance of M&As as a means of economic concentration and emergence in terms of major commercial or industrial projects, the laws of both the UAE and Qatar do not sufficiently address the issue of mergers or their goals and conditions. They also fail to regulate acquisitions or to otherwise specify when acquisitions become necessary for companies. Furthermore, the laws do not specify the rights of workers regarding their knowledge of or participation in M&As or developed adequate solutions for the negative impacts on companies workers in such processes. These laws do not provide the right for the Board of Directors of the transferor company to merge with the Board of Directors of the transferee company. Additionally, they also unsuccessfully address the minority shareholders right (those not interested in the merger) to exit the merged company and recover the value of their shares. Moreover, the UAE and Qatar have not developed appropriate solutions for the exchange of shares between companies involved in mergers in the case of dissimilarity between the actual values of the shares of both companies. This has notably led to jurisprudence and judiciary confusion between the concept of M&As, their legal nature and the legal basis or theory for the transfer of the rights and liabilities of employees, management and shareholders between companies involved in M&A operations. In accordance with legal texts, the above discussion, M&A legal theory and the theory of the agency contract between a company and its Board of Directors, the thesis argues that M&As should not lead to cutting labour contracts or negatively affect employee rights as long as corporate ventures remain in place and M&A operations do not lead to the liquidation of merged or acquired companies. Also, the thesis shows that a company is linked with its Board of Directors through a special form of agency contract, which justifies the transfer of the rights of the Board of Directors of the merged company with regards to the merging or new company management. The thesis also develops solutions and processes for the exchange of shares between merged companies when there are differences between the actual values of their shares, through the shareholders of the merged company buying shares from the merging company or by selling their shares to the merging company and recovering the value of their shares in cash. The study also recommends taking a set of procedural measures during M&As, modifying some of the relevant legal texts of the UAE and Qatar, which would mitigate the negative effects of mergers and acquisitions. Furthermore, this research suggests ways to improve such laws to reach the level of those of developed countries, in order to encourage mergers and acquisitions in the region

Resonant and Nonresonant All-Optical Switching Devices in GaAs/GaAlAs

The resonant refractive and absorptive optical nonlinearity of a GaAs/GaAlAs single quantum well waveguide are characterised; hh and Ih excitons are well resolved at room temperature. The unsaturated resonant nonlinear refractive index coefficient n2 was 1.4x10e-8 cm2/W, measured using the external Mach-Zehnder interferometric technique. It has been shown that the recovery time of the resonant nonlinearity is reduced to 125 ps (1/e recovery time), by placing the single quantum well close to the top surface. All-optical switching of an integrated asymmetric Mach-Zehnder interferometer is demonstrated and it was shown experimentally and theoretically that due to the absorption saturation, a complete switching is not possible. The nonresonant nonlinear optical properties of GaAlAs waveguide were characterised at photon energy below half the band gap

An Accurate Performance Analysis of Hybrid Efficient and Reliable MAC Protocol in VANET under Non-saturated Conditions

Vehicular Ad Hoc Networks (VANETs) is a technology supporting two types of applications, safety and service applications with higher and lower priorities respectively. Thereby, Medium Access Control (MAC) protocol is designed to provide reliable and efficient data broadcasting based on prioritization. Different from the IEEE 1609.4 (legacy), HER-MAC protocol is a new multi-channel MAC proposed for VANETs, offering remarkable performance with regards to safety applications transmission. This paper focuses on the analysis of packet delivery ratio of the HER-MAC protocol under non-saturated conditions. 1-D and 2-D Markov chains have been developed for safety and non-safety applications respectively, to evaluate mathematically the performance of HER-MAC protocol. The presented work has taken into account the freezing of the backoff timer for both applications and the backoff stages along with short retry limit for non-safety applications in order to meet the IEEE 802.11p specifications. It highlights that taking these elements into consideration are important in modeling the system, to provide an accurate estimation of the channel access, and guarantees that no packet is served indefinitely. More precise results of the system packet delivery ratio have been yield. The probability of successful transmission and collisions were derived and used to compute the packet delivery ratio. The simulation results validate the analytical results of our models and indicate that the performance of our models outperformed the existing models in terms of the packet delivery ratio under different number of vehicles and contention window

Centralized scheduling, routing tree in WiMAX mesh networks

In the last few years, demand for high speed internet access service has increased greatly so the IEEE 802.16 working group on broadband wireless access (BWA) is developing the worldwide interoperability for microwave access (WiMAX) standard for wireless metropolitan area networks (MANs) which aims to provide broadband wireless last mile access, easy deployment, and high speed data rate for large spanning area. This paper propose an efficient routing and collision free centralized scheduling (CS) algorithms using single channel single transceiver system in WiMAX mesh network, which introduces the cross layer concept between the network layer and media access controller (MAC) layer. The proposed approach has improved the system performance in the aspects of scheduling length, channel utilization ratio (CUR), and the throughput of the system

Ultrafast All-Optical Switching In Gaalas Directional-Couplers At 1.55 Mu-M Without Multiphoton Absorption

We demonstrate ultrafast, high throughput, all-optical switching in optimized, 2-cm-long, half- and full-beat-length nonlinear directional couplers operated at 1.55 mum, below half the band gap of Ga0.82Al0.18As. The long device length allowed the elimination of nonlinear loss and resulted in a switching peak power and energy of 85 W and 65 pJ, respectively

Review of network routing in IEEE 802.16 WiMAX mesh networks

The rapid growth of high-speed multimedia services for mobile, residential and small business customers has created an increasing demand for last mile broadband access. Technologies based on 802.16 which called WiMAX (Worldwide Interoperability Microwave Access) promises to deliver high data rates over large distances and deliver multimedia services and are expected to play a major role in high speed broadband delivery. Routing in Wireless Mesh Network (WMN) is challenging because of the unpredictable variations of the wireless environment. Traditional mechanisms have been proved that the routing performance would get deteriorated and ideal metrics must be explored. There are various challenges for the routing in WiMAX mesh such as delay, long transmission scheduling, and increasingly stringent Quality of Service (QoS) support and load balance and fairness limitations. The goal of this paper is to review some routing algorithms proposed by various authors for IEEE 802.16 mesh networks. This paper discusses the problem of routing for providing QoS, for minimizing interference, robustness and fairness in detail

Constructing routing tree centralized scheduling using multi-channel system in 802.16

The IEEE 802.16 standard defines WiMax (worldwide interoperability for microwave access) mesh network, using the base station (BS) as a coordinator for centralized scheduling. This paper proposes a centralized scheduling algorithm by constructing routing tree in WiMax mesh network, which introduces the cross-layer concept between the media access controller (MAC) and the network layers. The interference, hop-count, spatial reuse and quality of services (QoS) guarantee are considered. In our scheme, each node has one transceiver and can be tuned between multiple channels, intending to eliminate the secondary interference. The result of analysis shows this algorithm greatly improves the length of scheduling, channel utilization ratio (CUR) and average transmission scheduling

Limitation Due To 3-Photon Absorption On The Useful Spectral Range For Nonlinear Optics In Algaas Below Half Band-Gap

We report measurements of the spectral dispersion and the magnitude of three-photon absorption in Al0.18Ga0.82As for photon energies between one half and one third the band gap and show that a two-parabolic-band model is valid in this material. These results indicate that there is a limited spectral range below half the band gap in AlGaAs (and presumably all semiconductors) in which the bound electronic optical nonlinearity can be used without significant multiphoton absorption