231 research outputs found

    On Adaptive Extended Different Life Cycle of Product Design Strategy

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    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

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    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

    Wireless powered communication networks using peer harvesting

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    For an energy-constrained wireless network, energy harvesting (EH) is a promising technology to prolong the network life. Whether traditional near-field wireless power transfer (WPT) using inductive and resonant coupling or far-field WPT via radiated electromagnetic waves, both of them draw considerable research interests these years [1], [2]. In particular, the far-field WPT is meaningful for wireless powered communication (WPC) networks. A fundamental tradeoff was first studied for simultaneous wireless information and power transfer (SWIPT) in [3], [4]. These results aroused the interest of researchers. Subsequently, wireless communication with EH technology was presented in [5], [6]

    Research on Noise Reduction of Variable Speed Rotary Compressor with Large Capacity

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    With the increasing speed and capacity of variable-speed rotary compressors, the problem of noise especially low and medium frequency noise in the air conditioning system which can\u27t be solved by wrapping soundproof cotton has became more serious. In this paper, based on the noise problem of the rotor compressor with a working capacity of more than 80CC, the main frequency and the position of the noise source within 1000Hz are confirmed by simulation and experiment. Then on the base of this,the muffler and accumulator are respectively optimized and improved combining with Computer Aided Engineering (CAE) means. The final application results show that the optimized scheme can reduce noise by 6.1dB in 160Hz and 8.9dB in the frequency range of 500Hz to 800Hz, achieving good results

    Revisiting the characteristics of the spectral lags in short gamma-ray bursts

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    In this paper, we restudy the spectral lag features of short bright gamma-ray bursts (T90 < 2.6s) with a BATSE time-tagged event (TTE) sample including 65 single pulse bursts. We also make an investigation on the characteristics of ratios between the spectral lag and the full width at half maximum (FWHMFWHM) of the pulses, called relative spectral lags (RSLs). We draw the conclusions as follows: 1) Spectral lags of short GRBs are normally distributed and concentrated on around the value of 0.014 with 40 percent of them having negative lags. With K-S test, we find the lag distribution is identical with a normal one caused by white noises, which indicates the lags of the vast majority of short bursts are so small that they are negligible as Norris et al. have suggested.Comment: 10 pages, 3 figures, accepted for publication in MNRA

    Concept and Evidence of Tourist Risk Gaze

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    Gaze describes the experiential way that tourists perceive destinations during trips. Destination-related risks are inevitable in tourism; however, little attention has been given to the tourist gaze based on travel risk. Our research addresses this disparity by proposing and exploring the concept of tourist risk gaze. In Study 1, findings suggest that this type of gaze involves three interrelated aspects: risk information gaze, risky attraction gaze, and risky behavior gaze. In Study 2, we invited 50 Chinese university students to participate in an eye-tracking experiment to test tourist risk gaze. Participants displayed distinct visual attention patterns towards these three aspects when tourists encountered them during trips. This research offers a new lens through which to consider the tourist gaze and risk perception. It also introduces a novel eye-tracking method to analyze travel risk and the tourist gaze

    Advancing Control for Shield Tunneling Machine by Backstepping Design with LuGre Friction Model

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    Shield tunneling machine is widely applied for underground tunnel construction. The shield machine is a complex machine with large momentum and ultralow advancing speed. The working condition underground is rather complicated and unpredictable, and brings big trouble in controlling the advancing speed. This paper focused on the advancing motion control on desired tunnel axis. A three-state dynamic model was established with considering unknown front face earth pressure force and unknown friction force. LuGre friction model was introduced to describe the friction force. Backstepping design was then proposed to make tracking error converge to zero. To have a comparison study, controller without LuGre model was designed. Tracking simulations of speed regulations and simulations when front face earth pressure changed were carried out to show the transient performances of the proposed controller. The results indicated that the controller had good tracking performance even under changing geological conditions. Experiments of speed regulations were carried out to have validations of the controllers
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