In an attempt to identify motivating factors involved in decisions to publish in Open Access (OA) journals, individual interviews with biomedical faculty members at the University of North Carolina at Chapel Hill, a major research university, were conducted. The interviews focused on faculty identified as early adopters of OA/free full-text publishing. Searches conducted in PubMed and PubMed Central identified faculty from UNC-Chapel Hill who have published works in OA/free full-text journals. The searches targeted authors with multiple OA citations during a specified 18 month period. Semi-structured interviews were conducted with the most prolific OA authors. Individual interviews attempted to determine whether the authors were aware they published in OA journals, why they chose to publish in OA journals, what factors influenced their publishing decisions, and their general attitude towards OA publishing models. Interview questions were based on a review of the literature and consultation with a scholarly communication working group. The interview results were analyzed to see whether these faculty members made conscious efforts to publish in OA/free full-text journals, and if so why.

Fine-grained access control for XML is about controlling access to XML documents at the granularity of individual elements or attributes. This thesis addresses two problems related to XML access controls. The first is efficient, secure evaluation of XPath expressions. We present a technique that secures path expressions by means of query modification, and we show that the query modification algorithm is correct under a language-independent semantics for secure query evaluation. The second problem is to provide a compact, yet useful, representation of the access matrix. Since determining a user's privilege directly from access control policies can be extremely inefficient, materializing the access matrix---the net effect of the access control policies---is a common approach to speed up the authorization decision making. The fine-grained nature of XML access controls, however, makes the space cost of matrix materialization a significant issue. We present a codebook-based technique that records access matrices compactly. Our experimental study shows that the codebook approach exhibits significant space savings over other storage schemes, such as the access control list and the compressed accessibility map. The solutions to the above two problems provide a foundation for the development of an efficient mechanism that enforces fine-grained access controls for XML databases in the cases of query access.

Fine-grained access control for XML is about controlling access to XML documents at the granularity of individual elements or attributes. This thesis addresses two problems related to XML access controls. The first is efficient, secure evaluation of XPath expressions. We present a technique that secures path expressions by means of query modification, and we show that the query modification algorithm is correct under a language-independent semantics for secure query evaluation. The second problem is to provide a compact, yet useful, representation of the access matrix. Since determining a user's privilege directly from access control policies can be extremely inefficient, materializing the access matrix---the net effect of the access control policies---is a common approach to speed up the authorization decision making. The fine-grained nature of XML access controls, however, makes the space cost of matrix materialization a significant issue. We present a codebook-based technique that records access matrices compactly. Our experimental study shows that the codebook approach exhibits significant space savings over other storage schemes, such as the access control list and the compressed accessibility map. The solutions to the above two problems provide a foundation for the development of an efficient mechanism that enforces fine-grained access controls for XML databases in the cases of query access.

No description available.

Orthogonal Frequency Division Multiple Access (OFDMA) uplink systems have been adopted generally in wireless communication in recent years. By combining Orthogonal Frequency Division Multiplexing (OFDM) with Frequency Division Multiple Access (FDMA), OFDMA systems divide all subcarriers in frequency domain into several mutually exclusive subbands, and assign the subbands to different user, transmitting different kinds of data by the orthogonality between subcarriers. The users¡¦ Carrier Frequency Offsets (CFO) caused by Doppler effects and/or misadjusted local oscillators may destroy the orthogonality between subcarriers, then lead to Multiple Access Interference (MAI) for all users, the MAI may degrade the performance of bit error rate. Several MAI suppression or cancellation schemes have been investigated to mitigate the effect of MAI, however, these schemes work on the hypothesis of known CFOs. As the result, it is the crucial issue for the multiuser CFOs estimation in OFDMA uplink systems. In this paper, we propose the Minimum Mean Square Error Criterion (MMSEC) estimation scheme to achieve multiuser CFOs estimation in Additive White Gaussian Noise (AWGN) environment. By modifying the MAI suppression weighting in [9], the MMSEC scheme search desired user¡¦s true CFO with CFO trial parameter, while the CFO trial parameter is equal to true CFO, the modified MAI suppression weighting will suppress the MAI ideally and then separate the desired user¡¦s estimated signal from received signal. Thus the distribution of estimated signal is highly concentrated in each of quadrant in the signal constellation, and it will have the minimum mean square error in each of quadrant. Compare with the MUtiple SIgnal Classification (MUSIC) scheme [12] and the Estimation of Signal Parameter via Rotational Invariance Technique (ESPRIT) scheme [13], they deal with the fully loaded problem by extending cyclic prefix, that may cause the redundant power consumption or degrade data throughput, the advantage of the MMSEC scheme is that it can works on fully load without extending cyclic prefix. Because despite fully loaded, the CFO trial parameter search desired user¡¦s true CFO in reasonable range until it causes minimum mean square error. The simulation result shows that the non-fully loaded system mean square error (MSE) performance is superior to the MUSIC and ESPRIT schees at high signal to noise ratio, while system is fully loaded, the system MSE performance is also acceptable.

The Directory of Open Access Journals (DOAJ) is the world’s most authoritative list of scholarly, peer-reviewed, fully open access journals, and a “must” for libraries of all types. As of August 2007, DOAJ includes over 2,800 titles, over 10% of the world’s estimated 20-25,000 peer-reviewed scholarly journal titles. This is an impressive list; in terms of numbers of titles, DOAJ compares favorably with commercial journal packages. DOAJ is growing rapidly, at a rate of more than one title per calendar day. DOAJ’s highly functional and aesthetically pleasing interface features a number of search options, including a new search option for authors looking for open access or hybrid journals to publish in. DOAJ is freely available, and working towards economic sustainability through an optional membership / sponsorship program. This article examines the DOAJ membership program in some depth. Membership fees for libraries and library consortia are an incredible bargain. The membership fee for DOAJ’s 2,800 (and growing) title list is less than the average subscription cost for a single journal in any scientific discipline, and DOAJ represents significant staff time savings for libraries. The promotional benefits of DOAJ membership are important to position libraries for leadership in the internet age, and especially in the key emerging area of scholarly communications. DOAJ is a very popular service among libraries, with a strong reputation for quality; membership or sponsorship is likely to be highly beneficial to library service providers. As a free resource, DOAJ is strongly recommended for all libraries. DOAJ titles can be included in A-Z journal lists, library catalogues or websites, and subject-specific URLs can be added to subject guides or pathfinders.

There is growing concern that human access into areas of wildlife habitat and the management of that access has become one of the most significant issues in sustaining wildlife populations worldwide. Although access management is recommended throughout primary wildlife research and provincial land management plans as a means of wildlife management, limited research has been conducted on measuring the status of access or on access management strategies. Based on a review of the literature on resource management plans and provincial management strategies, this thesis identifies and describes fifteen potential ecological indicators for measuring and monitoring access and access management. Five key findings are summarized from this review. (1) Meaning and implementation of the term `access management' remains vague and ambiguous. (2) Measures of human access are often tied to large mammal management and studies. (3) Access management is a big question, encompassing cumulative impacts, and when viewed from a systems approach should consider ecological indicators across multiple levels of biological organization. (4) Attention is brought to two sub-types of indicators to monitor access management, land use indicators and wildlife use indicators. (5) Ecological indicators of access and access management share one similar data layer, GIS access infrastructure data.

No description available.

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.A.)--University of Hong Kong, 1999. / Includes bibliographical references. Also available in print.