There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

“Unpaired Image-to-Image Translation using Cycle-Consistent Adversarial Networks”の学習報告

The distributed nature and dynamic topology of Wireless Sensor Networks (WSNs) introduces very special requirements in routing protocols that should be met. The most important feature of a routing protocol, in order to be efficient for WSNs, is the energy consumption and the extension of the network's lifetime. During the recent years, many energy efficient routing protocols have been proposed for WSNs. In this paper, energy efficient routing protocols are classified into four main schemes: Network Structure, Communication Model, Topology Based and Reliable Routing. The routing protocols belonging to the first category can be further classified as flat or hierarchical. The routing protocols belonging to the second category can be further classified as Query-based or Coherent and non-coherent-based or Negotiation-based. The routing protocols belonging to the third category can be further classified as Location-based or Mobile Agent-based. The routing protocols belonging to the fourth category can be further classified as QoS-based or Multipath-based. Then, an analytical survey on energy efficient routing protocols for WSNs is provided. In this paper, the classification initially proposed by Al-Karaki, is expanded, in order to enhance all the proposed papers since 2004 and to better describe which issues/operations in each protocol illustrate/enhance the energy-efficiency issues.

Energy-Efficient Routing Protocols in Wireless Sensor Networks: A Survey

https://hal.archives-ouvertes.fr/hal-01009386/document

Energy efficiency in wireless sensor networks: A top-down survey

Given the explosive growth of data that needs to be transmitted and stored, there is a necessity to focus on developing better transmission and storage technologies. The main goal of this paper is to develop the best compression methods for climate data. By using data compression, significant reduction in the bits to encode the climate data can be accomplished without loss of any important information. In this paper, humidity and precipitation data are considered for compression. The methodology is based on differential encoding wherein the prediction of the sample being encoded is obtained according to the output of an ANN (multilayer perceptron) whose inputs are time, month, temperature, pressure, incoming shortwave radiation, incoming long wave radiation, outgoing shortwave radiation, outgoing long wave radiation and solar radiation data for humidity and time, month, temperature, humidity, incoming short wave radiation, outgoing shortwave radiation, incoming long wave radiation, outgoing long wave radiation, and solar radiation data for precipitation. The ANN model uses 3 layers and 27 neurons for prediction of humidity data and 2 layers and 20 neurons for precipitation data. The highest compression ratio for precipitation data is 8.96 which is observed for the month of October and for humidity data the highest compression ratio is 6.92 and it is observed in the month of June.

/pdf/lossless-compression-of-humidity-and-precipitation-data-445ri846gk.pdf

Lossless Compression of Humidity and Precipitation Data

In this paper we develop a feasibility algorithm for preemptively scheduling a given set of jobs with dimension and time requirements on a star graph network of given size with a given deadline. We show that the algorithm runs in /spl Oscr/(n log n) time when n is the number of jobs.

http://ieeexplore.ieee.org/iel3/4266/12232/00562908.pdf

Preemptive job scheduling in star graph networks

Subcube embeddability of the hypercube can be enhanced by introducing an additional dimension. A set of new dimensions, characterized by the Hamming distance between the pairs of nodes it connects, is introduced using a measure defined as the magnitude of a dimension. An enumeration of subcubes of various size is presented for a dimension parameterized by its magnitude. It is shown that the maximum number of subcubes for a Qn can only be attained when the magnitude of dimension is n-1 or n. It is further shown that the latter two dimensions can optimally increase the number of subcubes among all possible choices.

Optimal Subcube Embeddability in Hypercubes with Additional Dimension.

Regardless of the source language, text documents contain significant amount of redundancy. Data compression exploits this redundancy to improve transmission efficiency and/or save storage space. Conventionally, various lossless text compression algorithms have been introduced for critical applications, where any loss after recovery is intolerable. For non-critical applications, i.e. where data loss to some extent is acceptable, one may employ lossy compression to acquire superior efficiency. We use three recent techniques to achieve character-oriented lossy text compression: Letter Mapping (LM), Dropped Vowels (DV), and Replacement of Characters (RC), and use them as a front end anticipating to improve compression performance of conventional compression algorithms. We implement the scheme on English and Turkish sample texts and compare the results. Additionally, we include performance improvement rates for these models when used as a front end to Huffman and Arithmetic Coding algorithms. As for the future work, we propose several ideas to further improve the current performance of each model.

/pdf/fazlaliktan-yararlanarak-kayipli-metin-sikistirma-4865thduei.pdf

Fazlalıktan Yararlanarak Kayıplı Metin Sıkıştırma Gerçekleştirimi

Hierarchical networks may be divided into subnetworks having the same topological properties of the original network. The star graph, an example of hierarchical networks, has been studied extensively as a viable candidate for massively parallel systems. For a given number of faulty links and using a combinatorial approach, lower bounds on probability of having one or more (n − 1)-stars in an n-star are determined. An identification algorithm is presented to find an available (n − 1)-star in an n-star containing a set of faulty links.

Shahram Latifi

Papers

Lossless Compression of Humidity and Precipitation Data

Preemptive job scheduling in star graph networks

Optimal Subcube Embeddability in Hypercubes with Additional Dimension.

Fazlalıktan Yararlanarak Kayıplı Metin Sıkıştırma Gerçekleştirimi

A combinatorial study of substar reliability of the star network