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Yahoo!

CompanyLondon, United Kingdom
About: Yahoo! is a company organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Web search query. The organization has 26749 authors who have published 29915 publications receiving 732583 citations. The organization is also known as: Yahoo! Inc. & Maudwen-Yahoo! Inc.


Papers
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Proceedings ArticleDOI
05 Jul 2008
TL;DR: Theoretical results hold only when the exploration policy chooses ads independent of side information, an assumption that is typically violated by commercial systems, and it is shown how clever uses of the theory provide non-trivial and realistic applications.
Abstract: We examine the problem of evaluating a policy in the contextual bandit setting using only observations collected during the execution of another policy. We show that policy evaluation can be impossible if the exploration policy chooses actions based on the side information provided at each time step. We then propose and prove the correctness of a principled method for policy evaluation which works when this is not the case, even when the exploration policy is deterministic, as long as each action is explored sufficiently often. We apply this general technique to the problem of offline evaluation of internet advertising policies. Although our theoretical results hold only when the exploration policy chooses ads independent of side information, an assumption that is typically violated by commercial systems, we show how clever uses of the theory provide non-trivial and realistic applications. We also provide an empirical demonstration of the effectiveness of our techniques on real ad placement data.

143 citations

Journal ArticleDOI
TL;DR: The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts, and all lichen species showed the ability to induce apoptosis of HCT-116 cells.
Abstract: The antioxidative, antimicrobial and antiproliferative potentials of the methanol extracts of the lichen species Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri, Hypogymnia physodes and Cladonia foliacea were evaluated. The total phenolic content of the tested extracts varied from 78.12 to 141.59 mg of gallic acid equivalent (GA)/g of extract and the total flavonoid content from 20.14 to 44.43 mg of rutin equivalent (Ru)/g of extract. The antioxidant capacities of the lichen extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging. Hypogymnia physodes with the highest phenolic content showed the strongest DPPH radical scavenging effect. Further, the antimicrobial potential of the lichen extracts was determined by a microdilution method on 29 microorganisms, including 15 strains of bacteria, 10 species of filamentous fungi and 4 yeast species. A high antimicrobial activity of all the tested extracts was observed with more potent inhibitory effects on the growth of Gram (+) bacteria. The highest antimicrobial activity among lichens was demonstrated by Hypogymnia physodes and Cladonia foliacea. Finally, the antiproliferative activity of the lichen extracts was explored on the colon cancer adenocarcinoma cell line HCT-116 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) viability assay and acridine orange/ethidium bromide staining. The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts. All lichen species showed the ability to induce apoptosis of HCT-116 cells.

143 citations

Proceedings ArticleDOI
18 Aug 2008
TL;DR: This study provides an analytical basis for applying a P2P model rather than a client-server model to build large scale Internet media delivery systems and analyzes the effectiveness of media caching with a mathematical model.
Abstract: The commonly agreed Zipf-like access pattern of Web workloads is mainly based on Internet measurements when text-based content dominated the Web traffic. However, with dramatic increase of media traffic on the Internet, the inconsistency between the access patterns of media objects and the Zipf model has been observed in a number of studies. An insightful understanding of media access patterns is essential to guide Internet system design and management, including resource provisioning and performance optimizations.In this paper, we have studied a large variety of media workloads collected from both client and server sides in different media systems with different delivery methods. Through extensive analysis and modeling, we find: (1) the object reference ranks of all these workloads follow the stretched exponential (SE) distribution despite their different media systems and delivery methods; (2) one parameter of this distribution well characterizes the media file sizes, the other well characterizes the aging of media accesses; (3) some biased measurements may lead to Zipf-like observations on media access patterns; and (4) the deviation of media access pattern from the Zipf model in these workloads increases along with the workload duration.We have further analyzed the effectiveness of media caching with a mathematical model. Compared with Web caching under the Zipf model, media caching under the SE model is far less effective unless the cache size is enormously large. This indicates that many previous studies based on a Zipf-like assumption have potentially overestimated the media caching benefit, while an effective media caching system must be able to scale its storage size to accommodate the increase of media content over a long time. Our study provides an analytical basis for applying a P2P model rather than a client-server model to build large scale Internet media delivery systems.

143 citations

Journal ArticleDOI
TL;DR: Advances in chemotherapy treatments with the addition of new and novel drugs marching into clinics as standard treatments are highlighted based on evidence from clinical trials and from a better understanding of tumour biology that has transformed the outlook in breast cancer in both the adjuvant and metastatic setting.
Abstract: The use of cytotoxic chemotherapy in both advanced and early stage breast cancer has made significant progress in the last 10 years with several landmark studies identifying clear survival benefits for newer therapies. In spite of these developments the optimal approach for any specific patient can not be determined from a literature review or decision-making algorithm alone. Treatment choices are predominantly based on practice determined by individual or collective experience and the historical development of treatment within a locality. The improvement in the understanding of the molecular biological basis of breast cancer provides possible targets for novel therapies. Personalised therapies for breast cancer based on the molecular characteristics of the tumour could improve the risk: benefit ratio of current therapies. Increased improvements in the use of a panel of biomarkers will thus not only move us towards tailored therapies but will also spare a group of patients that do not benefit from adjuvant chemotherapy. At the same time a better understanding of tumour biology will also streamline the development of new regimens for those who are unlikely to benefit from existing drugs. This review will focus on the evidence for the use of chemotherapy and highlight advances in chemotherapy treatments with the addition of new and novel drugs marching into our clinics as standard treatments based on evidence from clinical trials and from a better understanding of tumour biology that has transformed the outlook in breast cancer in both the adjuvant and metastatic setting.

143 citations

Patent
10 Sep 2004
TL;DR: In this article, an online music purchasing system and method is disclosed in which a radio service (106) operates on a user's computer and is configured for receiving and playing digital radio representations of media content in a radio session.
Abstract: An online music purchasing system and method is disclosed in which a radio service (106) operates on a user's computer and is configured for receiving and playing digital radio representations of media content in a radio session. A content server (118) is configured for serving the digital radio representations of media content to the radio service (106), and a radio sequence server (122) is configured for serving a sequential list of currently-playing and previously-played media content of the radio session to the radio service (106). An account server (111) is configured for receiving a signal indicative of a user's desire to purchase a file of one of a currently-playing or previously-played media content. A download manager (104) is configured for downloading the file to the user's computer according to the signal indicative of the user's desire to purchase the file.

143 citations


Authors

Showing all 26766 results

NameH-indexPapersCitations
Ashok Kumar1515654164086
Alexander J. Smola122434110222
Howard I. Maibach116182160765
Sanjay Jain10388146880
Amirhossein Sahebkar100130746132
Marc Davis9941250243
Wenjun Zhang9697638530
Jian Xu94136652057
Fortunato Ciardiello9469547352
Tong Zhang9341436519
Michael E. J. Lean9241130939
Ashish K. Jha8750330020
Xin Zhang87171440102
Theunis Piersma8663234201
George Varghese8425328598
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20232
202247
20211,088
20201,074
20191,568
20181,352