Multicriteria group decision support for information systems project selection

This paper presents a fuzzy multicriteria group decision making approach for evaluating and selecting information systems projects. The inherent subjectiveness and imprecision of the evaluation process is modeled by using linguistic terms characterized by triangular fuzzy numbers. A new algorithm based on the concept of the degree of dominance is developed to avoid the complex and unreliable process of comparing fuzzy numbers usually required in fuzzy multicriteria decision making. A multicriteria decision support system is proposed to facilitate the evaluation and selection process. An information systems project selection problem is presented to demonstrate the effectiveness of the approach. © 2009 Springer Berlin Heidelberg

Fuzzy multicriteria decision support for information systems project selection

This paper presents a fuzzy multicriteria group decision making approach for selecting information systems projects. The inherent subjectiveness and imprecision of the selection process is modeled by using linguistic terms characterized by triangular fuzzy numbers. To avoid the complex and unreliable process of comparing fuzzy numbers usually required in fuzzy multicriteria analysis, a new algorithm is developed based on the degree of dominance and the degree of optimality concepts. A multicriteria decision support system is proposed to facilitate the evaluation and selection process. An information systems project selection problem is presented to demonstrate the effectiveness of the approach

Finite-time stability and stabilization for a class of nonlinear discrete-time descriptor switched systems with time-varying delay

This paper is concerned with the finite-time stability analysis and state feedback stabilization controller design fora class of nonlinear discrete-time descriptor switched systems with time-varying delay. First, by using the implicit function theorem and constructing a switched Lyapunov functional, sufficient conditions are developed which guarantee that the nonlinear discrete-time descriptor switched system with time-varying delay is regular, causal, has a unique solution in a neighborhood of the equilibrium point, and is uniformly finite-time stable. Then a delay-dependent condition on the existence of a finite-time state feedback controller is proposed. Finally, two numerical examples are given to show the effectiveness of the proposed methods

Hybrid fast damping control strategy for doubly fed induction generators against power system inter-area oscillations

Here, a hybrid fast damping control strategy based on bang-bang modulation is proposed for doubly fed induction generators (DFIGs) against inter-area oscillations. Since the changes in active power modulation of DFIG may result in its interactive effect with torsional oscillations, this study relies on the modulation of DFIG reactive power to rapidly attenuate the system's critical oscillation mode. In order to overcome the buffeting of the bang-bang modulation, the proposed control strategy is designed as a hybrid scheme consisting of three operating modes which are switched based on the amplitude of the detected critical oscillation mode. The required lead phase for the proposed control strategy is determined using frequency domain analysis using detailed dynamic model of the DFIG. A comprehensive test is carried out by conducting simulation studies on a modified two-area system including an aggregated wind farm. It has been shown that the proposed strategy damps inter-area oscillations much quicker than the conventional continuous damping controller. Simulation results also showed that the control scheme is robust to the operation point variation and identification errors for practical application

Assessing Profit of Prediction for SDN controllers load balancing

Software-defined networking (SDN) provides programmable control and centralized management in data centers, making it a popular architecture. The large scale of networks has required to propose the geographical distribution of logically centralized control plane to achieve scalability and reliability. For solving the load imbalance among multiple controllers associated with the statically configured control plane, a switch migration mechanism is proposed to admit dynamic load balancing. Many studies have been carried out for solving the control plane load balancing problem based on the switch migration mechanism. However, previous studies focus on migrating the switches when the controllers are overloaded, thereby, wasting time in the switch migration phase and resulting in high latency. To address these problems, we propose the Assessing Profit Of Prediction (APOP) scheme, a load-balancing strategy in the multiple-controllers control plane based on the overloaded state prediction and profit assessment. We introduce Taylor's formula to predict the flow change in the network and assess the profit of migrating switches in advance, in order to decrease the migration time and minimize the harmful effects during the migration phase. The result of simulation experiments shows that our scheme performs effectively in reducing the migration cost in control plane load balancing

Proven Secure Tree-based Authenticated Key Agreement for Securing V2V and V2I Communications in VANETs

Vehicular ad hoc networks (VANETs) are vulnerable to many kinds of security attacks, so it is necessary to design an authenticated key agreement (AKA) scheme for securing communication channels in VANETs. Existing AKA schemes in VANETs focus on securing vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I) communication, rather than V2V and V2I simultaneously. Further, few key updating mechanisms, which are secure, practical, and lightweight, exist in current VANETs AKA schemes. In this paper, we propose a proven secure AKA scheme for securing V2V and V2I communications in VANETs, which can be divided into two parts. The first part is a three-party authentication process in which vehicles, road side unit (RSU), and trust authority (TA) authenticate each other. The second part is the key agreement process, which is used in the key generation and updating processes. For this phase, we design a tree-based key agreement algorithm that considers two scenarios, i.e., the joining of an authenticated vehicle and the leaving of the vehicle. The formal security proof and the security analysis show that our proposed scheme satisfies session key security and the necessary security requirements in VANETs, respectively. The performance analysis demonstrates that our proposed scheme has an advantage over several representative AKA schemes in VANETs

Facile synthesis of Ge1-x Snx nanowires

We report a facile one-pot solution phase synthesis of one-dimensional Ge1-x Sn x nanowires. These nanowires were synthesized in situ via a solution-liquid-solid (SLS) approach in which triphenylchlorogermane was reduced by sodium borohydride in the presence of tin nanoparticle seeds. Straight Ge1-x Sn x nanowires were obtained with an average diameter of 60 ± 20 nm and an approximate aspect ratio of 100. Energy-dispersive x-ray spectroscopy (EDX) and powder x-ray diffraction (PXRD) analysis revealed that tin was homogeneously incorporated within the germanium lattices at levels up to 10 at%, resulting in a measured lattice constant of 0.5742 nm. The crystal structure and growth orientation of the nanowires were investigated using high-resolution transmission electron microscopy (HRTEM). The nanowires adopted a face-centred-cubic structure with individual wires exhibiting growth along either the 111, 110 or 112 directions, in common with other group IV nanowires. Growth in the 112 direction was found to be accompanied by longitudinal planar twin defects. © 2020 The Author(s). Published by IOP Publishing Ltd

Intensive blood pressure control after endovascular thrombectomy for acute ischaemic stroke (ENCHANTED2/MT): a multicentre, open-label, blinded-endpoint, randomised controlled trial

Background The optimum systolic blood pressure after endovascular thrombectomy for acute ischaemic stroke is uncertain. We aimed to compare the safety and efficacy of blood pressure lowering treatment according to more intensive versus less intensive treatment targets in patients with elevated blood pressure after reperfusion with endovascular treatment. Methods We conducted an open-label, blinded-endpoint, randomised controlled trial at 44 tertiary-level hospitals in China. Eligible patients (aged ≥18 years) had persistently elevated systolic blood pressure (≥140 mm Hg for >10 min) following successful reperfusion with endovascular thrombectomy for acute ischaemic stroke from any intracranial large-vessel occlusion. Patients were randomly assigned (1:1, by a central, web-based program with a minimisation algorithm) to more intensive treatment (systolic blood pressure target Findings Between July 20, 2020, and March 7, 2022, 821 patients were randomly assigned. The trial was stopped after review of the outcome data on June 22, 2022, due to persistent efficacy and safety concerns. 407 participants were assigned to the more intensive treatment group and 409 to the less intensive treatment group, of whom 404 patients in the more intensive treatment group and 406 patients in the less intensive treatment group had primary outcome data available. The likelihood of poor functional outcome was greater in the more intensive treatment group than the less intensive treatment group (common OR 1·37 [95% CI 1·07–1·76]). Compared with the less intensive treatment group, the more intensive treatment group had more early neurological deterioration (common OR 1·53 [95% 1·18–1·97]) and major disability at 90 days (OR 2·07 [95% CI 1·47–2·93]) but there were no significant differences in symptomatic intracerebral haemorrhage. There were no significant differences in serious adverse events or mortality between groups. Interpretation Intensive control of systolic blood pressure to lower than 120 mm Hg should be avoided to prevent compromising the functional recovery of patients who have received endovascular thrombectomy for acute ischaemic stroke due to intracranial large-vessel occlusion.</p

SCOPE: SCUBA-2 Continuum Observations of Pre-protostellar Evolution - survey description and compact source catalogue

We present the first release of the data and compact-source catalogue for the JCMT Large Program SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE). SCOPE consists of 850 μm continuum observations of 1235 Planck Galactic Cold Clumps (PGCCs) made with the Submillimetre Common-User Bolometer Array 2 on the James Clerk Maxwell Telescope. These data are at an angular resolution of 14.4 arcsec, significantly improving upon the 353 GHz resolution of Planck at 5 arcmin, and allowing for a catalogue of 3528 compact sources in 558 PGCCs. We find that the detected PGCCs have significant sub-structure, with 61 per cent of detected PGCCs having three or more compact sources, with filamentary structure also prevalent within the sample. A detection rate of 45 per cent is found across the survey, which is 95 per cent complete to Planck column densities of N(H2) > 5 × 10^21 cm^−2. By positionally associating the SCOPE compact sources with young stellar objects, the star formation efficiency, as measured by the ratio of luminosity to mass, in nearby clouds is found to be similar to that in the more distant Galactic Plane, with the column density distributions also indistinguishable from each other