Shortest hop multipath algorithm for wireless sensor networks

AbstractShortest hop or distance path is one of the most common methods used for relaying messages in a wide variety of networks. It provides an efficient message relaying to destination in terms of energy and time. There are many algorithms for constructing shortest hop or distance path. However, according to our knowledge, no algorithm for constructing a shortest hop multipath for wireless sensor networks (WSNs) has yet been proposed in the literature. In this paper, we propose a novel distributed shortest hop multipath algorithm for WSNs in order to generate energy efficient paths for data dissemination or routing. The proposed algorithm generates shortest hop braided multipath to be used for fault-tolerance or load-balancing. It guarantees the BFS tree and generates near optimal paths in O(V.D+V) message complexity and O(D2) time complexity regarding the communication costs towards the sink after termination of algorithm

First-line treatment of patients with HER2-positive metastatic gastric and gastroesophageal junction cancer

Fluoropyrimidine+cisplatin/oxaliplatin+trastuzumab therapy is recommended for the first-line treatment of HER2-positive metastatic gastric adenocarcinoma. However, there is no comprehensive study on which platinum-based treatment should be preferred. This study aimed to compare the treatment response and survival characteristics of patients with HER2-positive metastatic gastric or gastroesophageal junction (GEJ) cancer who received fluorouracil, oxaliplatin, and leucovorin (mFOLFOX)+trastuzumab or cisplatin and fluorouracil (CF)+trastuzumab as first-line therapy. It was a multicenter, retrospective study of the Turkish Oncology Group, which included 243 patients from 21 oncology centers. There were 113 patients in the mFOLFOX+trastuzumab arm and 130 patients in the CF+trastuzumab arm. The median age was 62 years in the mFOLFOX+trastuzumab arm and 61 years in the CF+trastuzumab arm (P = 0.495). 81.4% of patients in the mFOLFOX+trastuzumab arm and 83.1% in the CF+trastuzumab arm had gastric tumor localization (P = 0.735). The median progression-free survival (PFS) was significantly higher in the mFOLFOX+trastuzumab arm (9.4 months vs. 7.3 months, P = 0.024). The median overall survival (OS) was similar in both groups (18.4 months vs. 15.1 months, P = 0.640). Maintenance trastuzumab was continued after chemotherapy in 101 patients. In this subgroup, the median OS was 23.3 months and the median PFS was 13.3 months. In conclusion, mFOLFOX+trastuzumab is similar to CF+trastuzumab in terms of the median OS, but it is more effective in terms of the median PFS in the first-line treatment of HER2-positive metastatic gastric and GEJ cancer. The choice of treatment should be made by considering the prominent toxicity findings of the chemotherapy regimens

Dinamik sahneler için gerçek zamanlı global ışıklandırma algoritmalarına ilişkin yeni yaklaşımlar

Bu tez çalışmasında dinamik sahneler için gerçek zamanlı global ışıklandırma algoritmalarına ilişkin yeni yaklaşımlar öne sürülmüştür. Literatürde öne sürülen konu ile ilgili çalışmalar incelenmiş ve birbirlerini tamamlayan üç yeni yöntem geliştirilmiştir. Öne sürülen ilk yöntem, çevresel ışıkların önemine göre örneklenmesi üzerinedir. Küresel koordinatlarda iki boyutlu olarak ifade edilen çevresel ışık görüntüsü, Kd-ağacı yapısı kullanılarak bloklara bölünmektedir. Bu blokların önemine göre örneklenmesi, olasılıklarının basit bir model ile ifade edilmesi ile sağlanmıştır. Geliştirilen ikinci yöntem sahnedeki görünürlük testlerinin gerçek zamanlı olarak yapılabilmesini hedeflemiştir. Bu amaçla sahnedeki nesneler dışbükey parçalara bölünüp, uzaysal bir veri yapısında saklanmaktadır. Bu veri yapısı gezilerek test edilmesi gereken dışbükey parçalar tespit edilmektedir. Her parça, öne sürülen gerçek zamanlı dışbükey - ışın kesişim testi ile test edilebilmektedir. Öne sürülen son yöntem gerçek zamanlı olarak görüntü oluşturma denklemini hesaplamayı hedeflemiştir. Bu amaçla çift yönlü yansıma dağılım denklemi, küresel normal dağılım karışımları ile modellenmiştir ve görüntü oluşturma denklemi basitleştirilmiştir

A Simple Yet Fast Algorithm for the Closest-Pair Problem Using Sorted Projections on Multi-Dimensions

28th International Symposium on Computer and Information Sciences (ISCIS) -- OCT 28-29, 2013 -- Inst Henri Poincare, Paris, FRANCEWOS: 000333692000003We present a simple greedy algorithm, QuickCP, for finding the closest-pair of points on a plane. It is based on the observation that if two points are close to each other, then it is very likely that their sorted projections to x-axis and/or to y-axis will reflect that closeness. Therefore we order our search starting from the pairs with closest x-projections (and closest y-projections) to find the closest pair quickly and make a fast exit. Empirical data up to 2(26) (over 60 million points) indicates that this approach quickly detects the closest pair and it is, on average 70% faster than the classical divide-and-conquer algorithm registering, to the best of our knowledge, the fastest recorded solution times in the literature for the planar closest-pair problem. A second contribution of our work is that QuickCP can be used as part of the divide-and-conquer algorithms to handle small sub-problems. Measurements on data up to 2(26) points show that this co-operation speeds up the basic divide-and-conquer algorithm on average 50%