In this paper, new code equivalence relationships between a network code and an index code are studied. First, for a given index coding instance, equivalent network coding instances are derived, where an index code ac...
详细信息
In this paper, new code equivalence relationships between a network code and an index code are studied. First, for a given index coding instance, equivalent network coding instances are derived, where an index code achieving the maximum acyclic induced subgraph bound is converted to the corresponding network code and vice versa. Then, the code equivalence results are generalized to erroneous cases for both a given network coding instance and a given index coding instance, that is, code equivalences between a network code with link errors and an index code with side information errors.
The next generation of cellular networks deploying wireless distributed femtocaching infrastructure proposed by Golrezaei et al. is studied. By taking advantage of multihop communications in each cell, the number of r...
详细信息
The next generation of cellular networks deploying wireless distributed femtocaching infrastructure proposed by Golrezaei et al. is studied. By taking advantage of multihop communications in each cell, the number of required femtocaching helpers is significantly reduced. This reduction is achieved by using underutilized storage and communication capabilities in user terminals, which results in reducing the deployment costs of distributed femtocaches. A multihop index coding technique is proposed to code the cached contents in helpers to achieve orderoptimal capacity gains. As an example, we consider a wireless cellular system in which contents have a popularity distribution and demonstrate that our approach can replace many unicast communications with multicast communication. We will prove that simple heuristic linear index code algorithms based on graph coloring can achieve order-optimal capacity under Zipfian content popularity distribution.
This paper considers a single-input single-output broadcast channel with receiver side information. We find the optimal clique cover index code and the optimal transmission time allocation that minimize outage probabi...
详细信息
This paper considers a single-input single-output broadcast channel with receiver side information. We find the optimal clique cover index code and the optimal transmission time allocation that minimize outage probability when total transmission time is limited. As our problem is NP-hard, we first find the optimal time allocation for a given index code. Then, we describe a brute-force algorithm that finds the set of all decodable index codes and chooses the optimal one adopting the optimal time allocation. To reduce the computational complexity of the brute-force algorithm, we propose a pruning algorithm which solves the same problem using the Hasse diagram but does not harm the optimality. Our analysis reveals that the optimal index code is dependent on the channel conditions, not simply on the number of required transmissions, which implies that the index coding-channel coupling improves the outage performance. It is also shown that this claim is still valid for general scalar linear index coding. Our simulation results verify that our proposed schemes effectively reduce the outage probability compared to other reference schemes, and our pruning algorithm considerably reduces the computational complexity required for the brute-force algorithm.
Alpha particle induced reactions on the target element thulium were investigated up to 75 MeV, using foil-stack activation technique and Ge(Li) gamma ray spectroscopy method. Excitation functions for eight reactions o...
详细信息
Alpha particle induced reactions on the target element thulium were investigated up to 75 MeV, using foil-stack activation technique and Ge(Li) gamma ray spectroscopy method. Excitation functions for eight reactions of the type Tm-169(alpha, xn), x = 1-4;Tm-169(alpha, pxn), x = 3;and Tm-169(alpha, alpha-xn), x = 1,2,4 were investigated. Of these, four reactions Tm-169(alpha, p3n), Tm-169(alpha, alpha-n), Tm-169(alpha, alpha-2n) Tm-169(alpha, alpha-4n), were studied for the first time and in the remaining four reactions, some 19 new energy-point cross-sections were measured for the first time. The experimental cross-sections were compared with the predictions of pre-equilibrium hybrid model, as well as the more recent index model, using the initial exciton number, n0 = 4 (4p0h). Both the models show better agreement in respect of (alpha, xnyp) type of reactions. However they are equally bad for (alpha, alpha-xn) type of reactions which involve the alpha-particle in the exit channels, and for which some direct reaction contributions are indicated.
Alpha particle induced reactions in the target elements copper and tantalum were studied. The excitation functions of Cu-63(alpha, n) + Cu-65(alpha, 3n), Cu-65(alpha, 2n), Ta-181(alpha, 2n) and Ta-181(alpha, 4n) were ...
详细信息
Alpha particle induced reactions in the target elements copper and tantalum were studied. The excitation functions of Cu-63(alpha, n) + Cu-65(alpha, 3n), Cu-65(alpha, 2n), Ta-181(alpha, 2n) and Ta-181(alpha, 4n) were measured up to 75 MeV. Eight new energy point cross-sections were measured for the first time. The experimental results were compared with the predictions of updaed hybrid model (ALICE/85/300) as well as with index model using the initial exciton number n(o) = 4 (4poh) and level density parameter, a = A/8. A general agreement was found for all the reactions with both the models.
We modify the heuristic algorithm proposed by Kwak, et al., called the extended least difference greedy (ELDG) algorithm, to make it more efficient. The column-merging heuristic algorithm, which is one of the essentia...
详细信息
ISBN:
(纸本)9781538650417
We modify the heuristic algorithm proposed by Kwak, et al., called the extended least difference greedy (ELDG) algorithm, to make it more efficient. The column-merging heuristic algorithm, which is one of the essential parts in the ELDG algorithm, is found numerically not to be efficient for reducing the index codelength;besides, the result of the column-merging heuristic algorithm can be even longer than that of the original LDG algorithm. We detect when the column-merging heuristic algorithm give worse result than the result of the original LDG algorithm. Modified slightly, the proposed column-merging heuristic algorithm becomes efficient for reducing codelength. Additionally, we add the cycle-of-p-nodes detection algorithm, which is the generalized version of the cycle-of-three-node detection algorithm in the ELDG algorithm. It is numerically shown that roughly 20% of the index codelength reduction is achieved by the proposed ELDG algorithm compared to the LDG algorithm, while the conventional ELDG algorithm shows 10% of reduction rate compared to the LDG algorithm.
By means of analogy, this paper analyses the present functional hierarchyframe model for system maintainability, and presents an improved model. Practical applicationindicates that the improved model is visualized, mo...
详细信息
By means of analogy, this paper analyses the present functional hierarchyframe model for system maintainability, and presents an improved model. Practical applicationindicates that the improved model is visualized, more convenient and perfected over the perviousmodels.
暂无评论