483 research outputs found
On Adaptive Extended Different Life Cycle of Product Design Strategy
AbstractThe article uses research ways of following the whole lifespan of product and enterprise's development course to research strategy of company's product design and development. It announces enterprises of different nature, enterprises at different developing stage will adopt different mode strategy. It also announces close causality between development course of company and central technology and product. The result indicated in different developing stages such as company development period, crisis predicament period, lasting steadies period, improving by payback period, issues steadies secondary period, declining go and live period, enterprise should pursue different mode product tactics of research and development such as shrinking strategy, consolidating strategy, innovation keeping forging ahead strategy. Enterprise should break regular management mode to introduce different research and development mode to promote enterprise's competitiveness effectively
Implementation strategies of a contract-based MRI examination reservation process for stroke patients
International audienceTimely imaging examinations are critical for stroke patients due to the potential life threat. We have proposed a contract-based Magnetic Resonance Imaging (MRI) reservation process [1] in order to reduce their waiting time for MRI examinations. Contracted time slots (CTS) are especially reserved for Neural Vascular Department (NVD) treating stroke patients. Patients either wait in a CTS queue for such time slots or are directed to Regular Time Slot (RTS) reservation. This strategy creates "unlucky" patients having to wait for lengthy RTS reservation. This paper proposes and analyzes other contract implementation strategies called RTS reservation strategies. These strategies reserve RTS for NVD but do not direct patients to regular reservations. Patients all wait in the same queue and are served by either CTS or RTS on a FIFO (First In First Out) basis. We prove that RTS reservation strategies are able to reduce the unused time slots and patient waiting time. Extensive numerical results are presented to show the benefits of RTS reservation and to compare various RTS reservation strategies
Maximum relative excitation of a specific vibrational mode via optimum laser pulse duration
For molecules and materials responding to femtosecond-scale optical laser
pulses, we predict maximum relative excitation of a Raman-active vibrational
mode with period T when the pulse has an FWHM duration of 0.42 T. This result
follows from a general analytical model, and is precisely confirmed by detailed
density-functional-based dynamical simulations for C60 and a carbon nanotube,
which include anharmonicity, nonlinearity, no assumptions about the
polarizability tensor, and no averaging over rapid oscillations within the
pulse. The mode specificity is, of course, best at low temperature and for
pulses that are electronically off-resonance, and the energy deposited in any
mode is proportional to the fourth power of the electric field.Comment: 5 pages, 4 figure
Joint Optimization of Deployment and Trajectory in UAV and IRS-Assisted IoT Data Collection System
Unmanned aerial vehicles (UAVs) can be applied in many Internet of Things
(IoT) systems, e.g., smart farms, as a data collection platform. However, the
UAV-IoT wireless channels may be occasionally blocked by trees or high-rise
buildings. An intelligent reflecting surface (IRS) can be applied to improve
the wireless channel quality by smartly reflecting the signal via a large
number of low-cost passive reflective elements. This article aims to minimize
the energy consumption of the system by jointly optimizing the deployment and
trajectory of the UAV. The problem is formulated as a
mixed-integer-and-nonlinear programming (MINLP), which is challenging to
address by the traditional solution, because the solution may easily fall into
the local optimal. To address this issue, we propose a joint optimization
framework of deployment and trajectory (JOLT), where an adaptive whale
optimization algorithm (AWOA) is applied to optimize the deployment of the UAV,
and an elastic ring self-organizing map (ERSOM) is introduced to optimize the
trajectory of the UAV. Specifically, in AWOA, a variable-length population
strategy is applied to find the optimal number of stop points, and a nonlinear
parameter a and a partial mutation rule are introduced to balance the
exploration and exploitation. In ERSOM, a competitive neural network is also
introduced to learn the trajectory of the UAV by competitive learning, and a
ring structure is presented to avoid the trajectory intersection. Extensive
experiments are carried out to show the effectiveness of the proposed JOLT
framework.Comment: 11 pages, 7 figures, 4 table
Inserting Extra Train Services on High-Speed Railway
With the aim of supporting future traffic needs, an account of how to reconstruct an existing cyclic timetable by inserting additional train services will be given in this paper. The Timetable-based Extra Train Services Inserting (TETSI) problem is regarded as an integration of railway scheduling and rescheduling problem. The TETSI problem therefore is considered involving many constraints, such as flexible running times, dwell times, headway and time windows. Characterized based on an event-activity graph, a general Mixed Integer Program model for this problem is formulated. In addition, several extensions to the general model are further proposed. The real-world constraints that concerning the acceleration and deceleration times, priority for overtaking, allowed adjustments, periodic structure and frequency of services are incorporated into the general model. From numerical investigations using data from Shanghai-Hangzhou High-Speed Railway in China, the proposed framework and associated techniques are tested and shown to be effective
Heat Pump-Based Novel Energy System for High-Power LED Lamp Cooling and Waste Heat Recovery
Unlike incandescent light bulb, which radiates heat into the surroundings by infrared rays, light emitting diode (LED) traps heat inside the lamp. This fact increases the difficulty of cooling LED lamps, while it facilitates the recovery of the generated heat. We propose a novel energy system that merges high-power LED lamp cooling with the heat pump use; the heat pump can cool the LED lamp and at the same time recover the waste heat. In this way, a high percentage of the energy consumed by the LED lamp can be utilized. In this work, we developed a prototype of this energy system and conducted a series of experimental studies to determine the effect of several parameters, such as cooling water flow rate and LED power, on the LED leadframe temperature, compressor power consumption, and system performance. The experimental results clearly indicate that the energy system can lead to substantial energy savings
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