University of Winnipeg

About: University of Winnipeg is a education organization based out in Winnipeg, Manitoba, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 3235 authors who have published 6413 publications receiving 150564 citations. The organization is also known as: U of W.

A distributed content independent method for spam detection

Abstract: The amount of spam has skyrocketed in the recent past. Traditionally, spam was sent by single source mass mailers (spammers), making it relatively easy to screen out through the use of blacklists. Recently spammers started using botnets to send out the spam, rendering the blacklists ineffective. Although, content-based spam filters provide temporary relief, this is a never-ending cat-and-mouse game between spammers and filter developers. We propose a distributed, content independent, spam classification system that is specifically aimed at botnet generated spam and can be used in combination with existing spam classifiers. Our proposed system uses source identification in combination with a peer-to-peer based distributed database to identify e-mails that are likely to have originated from botnets. The system is distributed in order to provide a robust defense against denial-of-service attacks from the very same botnets. Lastly, our system is specifically designed to be used within the existing e-mail infrastructure. It does not require special hardware, changes to the underlying protocols, or changes to the mail transfer agents.

The Photoelectric Effect: Reconstructing the Story for the Physics Classroom

Abstract: The photoelectric effect is commonly used as the introductory topic for the study of quantum physics. However, a literature review reveals that besides various weaknesses and errors in the presentation of the history of the photoelectric effect, textbook presentations also contain incorrect presentations of the work function and the photon concept. In this paper, I present, in story form, five key episodes of the history of the photoelectric effect that are necessary for its accurate and adequate portrayal: (a) the discovery of the photoelectric effect, (b) the characterization of and initial explanation for the photoelectric effect, (c) Einstein’s revolutionary paper on the light quantum and its explanation for the photoelectric effect, and his, eventually, receiving the Nobel Prize despite not having his hypothesis accepted, (d) Millikan’s experimental verification of Einstein’s photoelectric equation despite not accepting Einstein’s hypothesis, and (e) Compton’s measurements and his theoretical explanation which produced the ultimate acceptance of Einstein’s hypothesis. The story, entitled “The Birth of the Photon Concept,” has been tested in a classroom setting and is proposed as an essential component in the process of developing sound instructional materials.

Social, blood/injury, and agoraphobic fears in patients with physically unexplained chronic pain: Are they clinically significant?

Abstract: Recently, there has been increased interest in the extent to which chronic pain patients fear and avoid activities that are thought to be related to the experience of pain. To date, however, few studies have evaluated the nature and extent of nonpain fears in these patients. The purpose of the present study was to address this paucity. The Fear Questionnaire was administered to 130 patients with physically unexplained chronic pain and 93 patients with a chronic condition unrelated to pain. Results indicated that the chronic pain patients were more fearful and avoidant of social interactions/situations and blood/injury than were the patient controls. Agoraphobia was minimal and did not differ significantly between groups. As well, the proportions of chronic pain patients indicating definite avoidance of particular situations related to blood/injury phobia (i.e., injection/minor surgery, hospitals, sight of blood, and thoughts of injury/illness) and social phobia (i.e., being watched/stared at, and speaking/acting to an audience) were significantly greater when compared to the patient controls. These results indicate that nonpain fear and avoidance are common in patients with chronic pain. Implications regarding the significance of these fears and avoidance behaviours on the experience and maintenance of pain symptoms and related disability are discussed. Anxiety 2:28–33 (1996). © 1996 Wiley-Liss, Inc.

China’s State-Owned Enterprises: Their Role, Job Creation, and Efficiency in Long-Term Perspective

Abstract: Since the early 1990s, China's state-owned industrial sector has experienced severe and increasing stress. When the reform process emerged in 1992 from its post-Tiananmen doldrums, China's policy and rhetoric on state-owned enterprises (SOEs) began shifting steadily. In 1994, the government announced a major program of reforms with the theme of transforming SOEs into "moder corporations." A new round of experiments began in selected enterprises and cities, but a few years later, observers were more agreed than ever that efforts to improve the efficiency of the SOEs had been inadequate. After years of fretting about mounting SOE losses, government policy shifted toward acceptance of a quiet but nevertheless large-scale privatization of smalland medium-sized SOEs. By 1997, the World Bank, which had until then shown a notable patience with China's SOEs, was calling for the selection of no more than one thousand industrial SOEs for continued state majority share ownership and was recommending a more passive state role in all SOEs. China's leadership appeared increasingly prepared to accept such recommendations. In what follows, we suggest a perspective on the role of SOEs in China's moder economic transformation, beginning with the period