588 research outputs found

    Numerical model of ultrasonic multi-channel data transfer for servicing subsea production complex

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    Various researchers focused on different problems, and we can conclude that a single effective communication design with a specific algorithm that could be used in all types of underwater channels was not found. The design of the transmission is highly dependent on the conditions of the canal, as various schemes are used in shallow and deep water, and various algorithms in turbulent and calm waters. The type of channel alignment also depends on parameters such as channel estimation and coding. The ever-growing demand for bandwidth, efficiency, spatial diversity and the performance of underwater acoustic communications has opened the door to using Multiple Input Multiple Output (MIMO) technology. In this paper, we propose a method of ultrasonic data transmission under water based on the MIMO technology (Many emitters, many receivers, or MIMO - Multilpe Input - Multiple Output). This approach will allow for multi-channel data transmission in water and significantly increase the speed of information transfer

    Sign-changing solutions for a Schrödinger-Kirchhoff-Poisson system with 4-sublinear growth nonlinearity

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    In this paper we consider the following Schrödinger–Kirchhoff–Poisson-type system where Ω is a bounded smooth domain of R3 , a > 0, b ≥ 0 are constants and λ is a positive parameter. Under suitable conditions on Q(x) and combining the method of invariant sets of descending flow, we establish the existence and multiplicity of signchanging solutions to this problem for the case that 2 < p < 4 as λ sufficiently small. Furthermore, for λ = 1 and the above assumptions on Q(x), we obtain the same conclusions with 2 < p < 12 5

    An MPCC Formulation and Its Smooth Solution Algorithm for Continuous Network Design Problem

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    Continuous network design problem (CNDP) is searching for a transportation network configuration to minimize the sum of the total system travel time and the investment cost of link capacity expansions by considering that the travellers follow a traditional Wardrop user equilibrium (UE) to choose their routes. In this paper, the CNDP model can be formulated as mathematical programs with complementarity constraints (MPCC) by describing UE as a non-linear complementarity problem (NCP). To address the difficulty resulting from complementarity constraints in MPCC, they are substituted by the Fischer-Burmeister (FB) function, which can be smoothed by the introduction of the smoothing parameter. Therefore, the MPCC can be transformed into a well-behaved non-linear program (NLP) by replacing the complementarity constraints with a smooth equation. Consequently, the solver such as LINDOGLOBAL in GAMS can be used to solve the smooth approximate NLP to obtain the solution to MPCC for modelling CNDP. The numerical experiments on the example from the literature demonstrate that the proposed algorithm is feasible.</p

    Selling luxury products online : the effect of a quality label on risk perception, purchase intention and attitude toward the brand

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    Many luxury brands and online retailers are struggling with how to sell luxury products online. Purchasing such premium priced brands online implies a high level of risk for consumers since their evaluation of the products cannot be based on direct, tangible experiences with the product. This study suggests that retailers can diminish the perceived risk by adding a quality label to a luxury product. However, the effectiveness of such quality label depends on the cultural orientation of the consumer. As such, we expect a quality label only to be effective for high uncertainty avoidance consumers. An analysis of secondary data from A.T. Kearney reveals a negative relation between a country's level of uncertainty avoidance (UA) and how favorable its consumer base is for transacting online, which might be an indication that even general online consumer behaviors (not luxury products per se) are perceived as highly risky in high uncertainty avoidance cultures. In addition, an experimental study using a 2 (Quality label vs. no label) by 2 (luxury vs. non-luxury purchase) between-subjects design reveals that for a luxury brand, a quality label reduces the risk perception and in turn leads to higher purchase intention and attitude toward the brand for high UA individuals

    An MPCC Formulation and Its Smooth Solution Algorithm for Continuous Network Design Problem

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    Continuous network design problem (CNDP) is searching for a transportation network configuration to minimize the sum of the total system travel time and the investment cost of link capacity expansions by considering that the travellers follow a traditional Wardrop user equilibrium (UE) to choose their routes. In this paper, the CNDP model can be formulated as mathematical programs with complementarity constraints (MPCC) by describing UE as a non-linear complementarity problem (NCP). To address the difficulty resulting from complementarity constraints in MPCC, they are substituted by the Fischer-Burmeister (FB) function, which can be smoothed by the introduction of the smoothing parameter. Therefore, the MPCC can be transformed into a well-behaved non-linear program (NLP) by replacing the complementarity constraints with a smooth equation. Consequently, the solver such as LINDOGLOBAL in GAMS can be used to solve the smooth approximate NLP to obtain the solution to MPCC for modelling CNDP. The numerical experiments on the example from the literature demonstrate that the proposed algorithm is feasible.</p
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