This paper investigates the use of tone reservation for optical orthogonal frequency-division multiplexing (OFDM) systems in a short-range intensity-modulated, direct-detected (IM/DD) channel. In order to avoid any as...
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ISBN:
(纸本)9781467303231
This paper investigates the use of tone reservation for optical orthogonal frequency-division multiplexing (OFDM) systems in a short-range intensity-modulated, direct-detected (IM/DD) channel. In order to avoid any asymmetric clipping of the bipolar OFDM signal and associated nonlinear distortion, some of the tones/subchannels are reserved to produce a negative peak cancellation (NPC) signal. This approach guarantees a unipolar output and hence eliminates all in-band and out-of-band distortion. With an arbitrary reserved set, a linear programming (LP) problem can be formulated to optimally solve the frequency-domain signal design problem. Simulation results suggest that this method offers greater flexibility and a better trade-off between power and spectral efficiency for a given link budget.
Locally repairable codes are used in distributed storage networks to minimise the number of survived nodes required to repair a failed node. However, the robustness of these codes is a main concern since locally repai...
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ISBN:
(纸本)9781479959990
Locally repairable codes are used in distributed storage networks to minimise the number of survived nodes required to repair a failed node. However, the robustness of these codes is a main concern since locally repair procedure may fail when there are multiple node failures. This paper proposes a new class of robust locally repairable codes which guarantees that a failed node can be repaired locally even when there are multiple node failures. Upper bound on the size of robust locally repairable codes using linear programming tools are obtained and examples of robust locally repairable codes attaining these bounds are constructed.
In this paper we provide a linear programming relaxation algorithm for scheduling problem with controllable processing times. This problem is NP-hard even if there are no precedence constraints between the jobs. We pr...
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ISBN:
(纸本)9781424442461
In this paper we provide a linear programming relaxation algorithm for scheduling problem with controllable processing times. This problem is NP-hard even if there are no precedence constraints between the jobs. We prove that the performance ratio of the algorithm is 4.
We propose a new boosting algorithm based on a linear programming formulation. Our algorithm can take advantage of the sparsity of the solution of the underlying optimization problem. In preliminary experiments, our a...
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ISBN:
(纸本)9783642047466
We propose a new boosting algorithm based on a linear programming formulation. Our algorithm can take advantage of the sparsity of the solution of the underlying optimization problem. In preliminary experiments, our algorithm outperforms a state-of-the-art LP solver and LPBoost especially when the solution is given by a small set of relevant hypotheses and support vectors.
The linear programming method is applied to the space U-n(C) of unitary matrices in order to obtain bounds for codes relative to the diversity sum and the diversity product. Theoretical and numerical results improving...
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ISBN:
(纸本)9781424422562
The linear programming method is applied to the space U-n(C) of unitary matrices in order to obtain bounds for codes relative to the diversity sum and the diversity product. Theoretical and numerical results improving previously known bounds are derived.
In linear programming, many students find it difficult to translate a verbal description of a problem into a valid mathematical model. To better understand this, we examine the existing characteristics of college engi...
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In linear programming, many students find it difficult to translate a verbal description of a problem into a valid mathematical model. To better understand this, we examine the existing characteristics of college engineering students' errors across linear programming (LP) problems. We examined textbooks to identify the types of problems typically found in introductory linear programming courses. We then developed a comprehensive set of tasks and analyzed students' work to create a taxonomy of the errors and issues that students exhibited. From our findings, we define four categories of identified error types: (1) decision variable errors, (2) variable relationship errors, (3) notation errors, and (4) form errors. This study contributes to the research by investigating students' work in an area of undergraduate mathematics that has not been heavily explored before. Findings suggest specific areas of focus for future work in helping students develop their understanding of linear programming models and mathematical modeling in word problems in general.
In order to improve the throughput of network and ensure the quality of user experience, more small stations has been densely deployed in cellular networks. And consumption of fossil fuel will increase rapidly, which ...
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ISBN:
(纸本)9781509057597
In order to improve the throughput of network and ensure the quality of user experience, more small stations has been densely deployed in cellular networks. And consumption of fossil fuel will increase rapidly, which has brought serious challenges to the mobile operators in cost control and the ecological environment. With the development of renewable energy and smart grid, great changes have taken place in energy structure and energy utilization of the cellular network. The future trend of cellular networks will present a multi-source power. Traditional grid as the main body, centralized powering the base station form the wide area power grid, to maintain the basic power of wireless network. As a supplement, green base station can combine the set of equipment, base station, storage battery and charge controller together to achieve micro electric power network by multi-sources energy harvesting technology. However, the harvest of the renewable energy is influenced by the time-space instability. The demand of users and the consumption of the cellular networks are also influenced by space-time instability. Therefore, this paper proposes a model of the flexible configuration of energy through the energy management unit(EMU), through energy cooperation between base stations and smart grid, we can get optimal energy configuration. By analyzing the scenario of N time slots, m base station, we solve the optimal energy profiles for each time slots according to the greedy algorithm and linear programming, and then the relevant simulation will validate the algorithm. By using the algorithm to realize the energy cooperation according to the demands of each node, we can recede the instability of the process of energy harvesting. And we can achieve the goal of optimizing the efficient use of clean energy.
Solving large-scale optimization problems requires an integration of data-analysis and data-manipulation capabilities. Nevertheless, little attempt has been made to facilitate general linear programming solvers for da...
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ISBN:
(纸本)9789728865825
Solving large-scale optimization problems requires an integration of data-analysis and data-manipulation capabilities. Nevertheless, little attempt has been made to facilitate general linear programming solvers for database environments. Dozens of sophisticated tools and software libraries that implement linear programming model can be found. But, there is no database-embedded linear programming tool seamlessly and transparently utilized for database processing. The focus of this study is to fill out this kind of technical gap of data analysis and data manipulation, in the event of solving large-scale linear programming problems for the applications built on the database environment. Specifically, this paper studies the representation of the linear programming model in relational structures and the computational method to solve the linear programming problems. Foundations for and preliminary experimental results of this study are presented.
Discusses the use of optimizing techniques such as linear programming (LP) in managerial decision making. Argues that while LP has always offered a powerful tool for solving allocation type problems, the technique was...
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