A Comparative Study of mLAN and CobraNet Technologies and their use in the Sound Installation Industry
- Authors: Klinkradt, Bradley , Foss, Richard
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427331 , vital:72431 , https://www.aes.org/e-lib/browse.cfm?elib=12593
- Description: This paper highlights the two interconnection technologies of CobraNet and mLAN, and provides a comparative study of these technologies and their applicability to the sound installation industry, through a discussion of constraints inherent within such an installation. Issues such as the adherence to standards, costs, latency, speed, connection management, and the control and monitoring of devices are explored.
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- Date Issued: 2003
A digital watermarking scheme for Bezier surfaces
- Authors: Chadwick, J , Bangay, Shaun D , Wentworth, Peter E
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432769 , vital:72898 , https://www.cs.ru.ac.za/research/groups/vrsig/pastprojects/046watermarking/paper01.pdf
- Description: Owners and vendors are increasingly publishing their materials in digital form. Because such materials can be exactly copied, a mechanism is required that will protect the legitimate owners of these works, by providing proof of original ownership. Digital watermarking has now become one accepted method of establishing ownership of digital materials. The owner of a work embeds a pattern, called a digital watermark, in the content. This embedded watermark is normally undetectable, but its presence can be demonstrated by the owner of the work or his agent, thereby proving ownership. Digital watermarking has been used for many types of multimedia content, primarily audio, video and flat images. Recently, interest has been shown in applying digital watermarking schemes to 3D surfaces, in various formats. In this paper, we examine a method whereby a digital watermark can be embedded in a Bezier surface. A prototype watermarking method for such surfaces is presented, with some experimental results, and a discussion of directions for future research.
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- Date Issued: 2003
A lightwave 3d plug-in for modeling long hair on virtual humans
- Authors: Patrick, Deborah , Bangay, Shaun D
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432953 , vital:72916 , https://doi.org/10.1145/602330.602360
- Description: Multimedia applications today make use of virtual humans. Generating realistic virtual humans is a challenging problem owing to a number of factors, one being the simulation of realistic hair. The difficulty in simulating hair is due to the physical properties of hair. The average human head holds thousands of hairs, with the width of each hair often smaller than the size of a pixel. There are also complex lighting effects that occur within hair. This paper presents a LightWave 3D plug-in for modeling thousands of individual hairs on virtual humans. The plug-in allows the user to specify the length, thickness and distribution of the hair, as well as the number of segments a hair is made up of. The plug-in is able to add hairs to a head model, which the user then modifies to define a hairstyle. The hairs are then multiplied by the plug-in to produce many hairs. By providing a plug-in that does most of the work and produces realistic results, the user is able to produce a hairstyle without modeling each individual strand of hair. This greatly reduces the time spent on hair modeling, and makes the possibility of adding realistic long hair to virtual humans reasonable.
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- Date Issued: 2003
A New Connection Management Architecture for the Next Generation of mLAN
- Authors: Foss, Richard , Fujimori, J I
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427376 , vital:72434 , https://www.aes.org/e-lib/browse.cfm?elib=12539
- Description: mLAN is a networking technology based on the IEEE 1394 standard that allows for the transport of audio and music control data between audio devices. In the original implementation of mLAN, software within each mLAN node hosted by an audio device contained high level plug abstraction and connection management software. mLAN-B is the next generation mLAN architecture that splits the connection management function between workstation and device. The high level connection management and plug abstraction capability resides on the workstation, while a thin low level connection management capability is left on the device. This approach reduces cost and complexity on the device side and ensures that mLAN systems can be easily upgraded.
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- Date Issued: 2003
A new public sphere?: outstanding issues
- Authors: Wasserman, Herman , de Beer, Arrie
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159142 , vital:40272 , https://hdl.handle.net/10520/EJC146261
- Description: It is widely accepted that a healthy public sphere is a necessity for democracy, and that the media can facilitate debate in this sphere. In the years since democratisation in South Africa, the media's freedom to fulfil this role has been jealously guarded.
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- Date Issued: 2003
A Performance Comparison of Web Development Technologies to Distribute Multimedia across an Intranet
- Authors: Swales, D , Sewry, David , Terzoli, Alfredo
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427501 , vital:72443 , https://www.researchgate.net/profile/Alfredo-Ter-zoli/publication/237337386_A_Performance_Comparison_of_Web_Development_Technologies_to_Distribute_Multimedia_across_an_Intranet/links/0c9605298fdf33d7c0000000/A-Performance-Comparison-of-Web-Development-Technologies-to-Distribute-Multimedia-across-an-Intranet.pdf
- Description: In recent years the World Wide Web has transformed into a dynamic, interactive medium, exposing a proliferation of on-line services that dis-tribute large quantities of multimedia. This has increased awareness of the need to select an appropriate Web programming technology when creating Webbased services. This paper compares three dynamic Web programming technologies from the point of view of performance in multimedia distribution. In particular, this paper examines Sun Microsys-tem’s Java Server Pages (JSP), Microsoft’s Active Server Page’s (ASP) and the more recent ASP .NET. The comparison is based on testing applications that distribute multiple images from an Oracle 9i database to Web-enabled clients. Previous research conducted by Oracle indi-cates that JSP and the underlying Java platform outperform ASP. The results in this paper, however, do not agree with Oracle’s statement as JSP tends to be marginally slower than ASP.
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- Date Issued: 2003
A solution community: ways that work
- Authors: du Toit, Peter
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159112 , vital:40268 , https://hdl.handle.net/10520/EJC146301
- Description: It begins in the Southern African country of Zambotswa in a place called Anytown. Population: 540 000. The owner-editor of the Anytown Farmers' Weekly (AFW) has died and the Big Media Company, with its substantial assets across the country, has bought out his struggling paper.
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- Date Issued: 2003
Africa: Media
- Authors: Garman, Anthea
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158752 , vital:40225 , https://hdl.handle.net/10520/EJC146281
- Description: Those are our twin concerns as we move into this new moment in human history which is being called the "Information Society" or the "Information Age".
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- Date Issued: 2003
An mLAN Connection Management Server for Web-Based, Multi-User, Audio Device Patching
- Authors: Foss, Richard , Fujimori, J I , Klinkradt, Bradley , Bangay, Shaun D
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427404 , vital:72436 , https://www.aes.org/e-lib/browse.cfm?elib=12397
- Description: A connection management server has been developed that enables connections to be made between mLAN-compatible audio devices, via a client web browser on any web-enabled device, such as a laptop or PDA. The connections can also be made across IEEE1394 bridges, and will allow for the transport of audio and music data between mLAN devices on the same or separate IEEE 1394 buses. Multiple users will be able to make and break connections via the server.
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- Date Issued: 2003
Asterisk: A converged tdm and packet-based communications system
- Authors: Penton, J , Terzoli, Alfredo
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427547 , vital:72446 , https://citeseerx.ist.psu.edu/document?repid=rep1andtype=pdfanddoi=70080710a6f96bf1c071be14a8b21c17ff8cbc4d
- Description: Converged TDM and packet-based communications systems are a popular topic in computer science and telecommunications arenas. This paper discusses a system called Asterisk that is an open source hybrid TDM and packet voice platform. Asterisk is designed to interface any piece of telephony hardware or software with any telephony application. This makes Asterisk a powerful component that can be easily used in NGN softswitches, conferencing servers and Private Branch eXchanges (PBX). Asterisk has been deployed in the Rhodes University Computer Science Department’s VoIP environment and integrated with our existing H. 323 and SIP packet-based networks. This paper discusses the de-ployment of Asterisk, its interworking with our H. 323 and SIP networks and the functionality it offers in terms of a converged TDM and packet-based communications system.
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- Date Issued: 2003
Capital E for events: ways that work: useful solutions
- Authors: Garman, Anthea
- Date: 2003
- Language: English
- Type: text , article
- Identifier: vital:38359 , http://hdl.handle.net/10520/EJC146297
- Description: You would think being located in a small town in one of the most impoverished provinces in South Africa would be a drawback for making media. But a small town is a reachable, convenient laboratory environment for student journalists - and never more so than when the National Arts Festival comes to Grahamstown during the winter vacation.
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- Date Issued: 2003
Direct-use value of smallholder crop production in a semi-arid rural South African village
- Authors: Dovie, Delali B K , Witkowski, Ed T F , Shackleton, Charlie M
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181595 , vital:43750 , xlink:href="https://doi.org/10.1016/S0308-521X(02)00124-5"
- Description: The monetary value of natural resources used by rural communities for subsistence is important when addressing issues affecting the livelihoods of impoverished rural households. There is therefore the need to attribute monetary values to non-marketed products from smallholder production systems in order to reliably account for resource availability and usage to further sound policy decisions. The objective of this paper is to present an empirical analysis of the direct-use and traded values of crop production by households, and to discuss the implications for policy development. The study was undertaken in combination with an evaluation of other livelihood sectors in Thorndale, a semi-arid rural village in the Limpopo province of South Africa. The net direct-use value of crops was estimated at $443.4 per household per annum across the village. Maize (Zea mays), watermelon (Citrullus, vulgaris), peanuts (Arachis hypogaea) and common beans (Phaseolus vulgaris) contributed over 90% to the total direct-use value of crops. Maize alone contributed 40% of this value per household at an estimated $652/ha. Marketing of resources was not a common practice, limited to only maize and peanuts. Farming was basically a rain-fed–mixed cropping system with low production inputs. Farmer support services, human capital development and tenure security were major areas identified for policy development.
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- Date Issued: 2003
Dynamic run-time application development using CORBA objects and XML in the field of distributed GIS
- Authors: Preston, Michael , Clayton, Peter G , Wells, George C
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430500 , vital:72695 , https://doi.org/10.1080/1365881021000026557
- Description: The research presented describes our approach to enabling content developers and end-users to create and/or customise distributed GIS applications dynamical-ly at run-time through the incorporation of GIS services, implemented as stand-alone components or CORBA Objects, with a specialised XML descriptor. It also looks at some of the design considerations that must be dealt with by both the client-application developer as well as the service developer, including the GIS service description, associated GUI and help system.
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- Date Issued: 2003
Editorial: the policy-in-practice nexus
- Authors: Lotz-Sisitka, Heila , Obol, Charles , Nhamo, Godwell
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67389 , vital:29083 , https://www.ajol.info/index.php/sajee/article/view/122661/112205
- Description: publisher version , Environmental policy development and implementation has become a ‘hot topic’ in southern Africa, following global imperatives for countries around the world to articulate their intentions to become more sustainable through public policy. Many policies in the region have been developed with the support of large scale donor funding. Much of the funding is often allocated to policy development processes rather than policy implementation processes, and many countries have experienced ‘gaps’ between policy intention and policy playing out in the field. Recently the Southern African Development Community’s Regional Environmental Education Programme (SADC REEP) appointed an environmental education policy advisor to influence regional policy (our Guest Editor, Charles Obol).This edition of the journal, funded by SADC REEP, aims to provide perspective on the policy-in-practice nexus in southern Africa.
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- Date Issued: 2003
Effect of pictograms on readability of patient information materials:
- Authors: Mansoor, Leila E , Dowse, Roslind
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157003 , vital:40078 , https://0-doi.org.wam.seals.ac.za/10.1345/aph.1C449
- Description: To design, develop, and evaluate a simple, understandable medicine label and patient information leaflet (PIL) for nystatin suspension, and to assess the effect of incorporating pictograms on understanding in low-literate participants.
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- Date Issued: 2003
Electrochemical behavior and detection of dopamine and ascorbic acid at an iron (II) tetrasulfophthalocyanine modified carbon paste microelectrode
- Authors: Oni, Joshua , Westbroek, Philippe , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290279 , vital:56735 , xlink:href="https://doi.org/10.1002/elan.200390104"
- Description: In this article the electrocatalytic behavior of an iron(II)tetrasulfophthalocyanine modified carbon paste microelectrode for the oxidation of dopamine (DA) and ascorbic acid (AA) is described. Although the oxidation potential of ascorbic acid is shifted by over 100 mV to more positive potentials, no peak separation could be obtained. This can be explained by the immediate homogeneous reduction of the oxidation product of dopamine by ascorbic acid in solution. However, this reaction induces a shift of the half-wave potential as a function of ratio of concentration of dopamine to ascorbic acid (cDA/cAA). Therefore it was possible to determine the cAA and cDA from this potential shift and the experimental peak current. Detection limits of 4.5±0.2×10−7 and 7.5±0.5×10−7 mol L−1 were obtained respectively for dopamine and ascorbic acid for cDA/cAA>0.01.
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- Date Issued: 2003
Electrochemical behaviour of thiol-derivatised zinc (II) phthalocyanine complexes and their self-immobilised films at gold electrodes
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290295 , vital:56737 , xlink:href="https://doi.org/10.1016/j.microc.2003.08.002"
- Description: Electrochemical properties of novel, peripherally substituted zinc phthalocyanine complex, octa(4-methylphenylthio-) phthalocyaninatozinc(II) [ZnPc(SC6H4CH3)8] (1a) in DMF solution are presented. This complex showed five quasi-reversible/reversible, diffusion-controlled redox couples. Solution voltammetry of 1a showed little contrast with that of its alkythiol-derivative, octabutylthiophthalocyaninatozinc(II) [ZnPc(SC4H9)8] (1b) in that both thiol-substituents tend to show electron-withdrawing influence on the phthalocyanine ligands; complex 1a showing easier reduction and more difficult to oxidation when compared to 1b and other alkyl derivatives. The voltammetric features of the solid ultrathin films of 1a and 1b, immobilized on gold electrodes via the self-assembling technique, are also presented. Interestingly, the self-assembled films are stable and reproducible and provide good suppression to the following Faradaic processes; gold surface oxidation, solution ion species and underpotential deposition (UPD) of copper.
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- Date Issued: 2003
External and domestic sources of foreign policy ambiguity: South African foreign policy and the projection of pluralist middle power
- Authors: Bischoff, Paul, 1954-
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161442 , vital:40627 , https://doi.org/10.1080/0258934032000147291
- Description: As a pluralist middle power, post-apartheid South Africa seeks to generate successful foreign policy initiatives at bilateral, multilateral and regional levels in order to shape international outcomes. In this endeavour, it has three important political resources – a recognition of its geo-political position and importance as a democratic yardstick and reformer; its acceptance of a transnational, neo-liberal elite alliance and finally, recognition of its leadership role from forces wishing to challenge African political establishments. However, the international and domestic political environment which in the mid-1990s was favourable towards middle-power initiative and reform has narrowed.
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- Date Issued: 2003
Fuelwood availability and use in the Richtersveld National Park, South Africa
- Authors: Shackleton, Charlie M , Guthrie, G , Keirungi, J , Stewart, J
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181461 , vital:43736 , xlink:href=" https://doi.org/10.4102/koedoe.v46i2.66"
- Description: Concern has been voiced about the possible over-use of fuelwood from the riparian fringe by pastoralist herders in the Richtersveld National Park (RNP). This coincided with the current examination and modelling of the supply and use of ecosystem goods and services in the Gariep Basin as part of the Southern African Millennium Assessment (SAfMA). This paper reports on a study to index the current availability of deadwood within the riparian zone of RNP, its relationship with proximity to human habitation, and species preferences of the local herders. Deadwood availability was assessed per woody species and on the ground in 12 transects within the riparian fringe. Herders were interviewed regarding their species preferences, and the composition of woodpiles was examined. There was no relationship between the percentage of attached deadwood on the tree, or the percentage deadwood ground cover, and the distance from herder stockposts. Euclea pseudobenus and Tamarix usneoides were the dominant species in the riparian fringe. There was strong selection for Ziziphus mucronata as a fuelwood species and only marginal or random selection for E. pseudobenus. Tamarix usneoides and Prosopis sp. were abundant in the riparian zone, but were not used for fuelwood. There was a significant difference between species with respect to the mean proportion of the stem that was dead, the highest being Z. mucronata (± 28 % deadwood), followed by T. usneoides (± 12 %). Most of the Prosopis trees had no deadwood. Across all species, the mean percentage dead per tree was approximately 15 %. Additionally, detached deadwood covered just less than 9 % of ground area, averaged across all plots and transects. All the variables measured indicated that there seems to be little need for concern over the current fuelwood extraction activities of pastoralists within the RNP. There was no clear evidence of cutting of branches or deadwood. The abundance of both attached and detached deadwood was not depleted close to human habitation. There was still abundant deadwood, even on preferred species. The most preferred species (Ziziphus mucronata) had the greatest mean proportion of deadwood. The herders stated that they only used deadwood, and that there was plenty. They rarely used driftwood washed down the river, although there was an abundance of it. Thus, overall, there was no sign of depletion of the deadwood resource, even on favoured species, or degradation of the productive capacity for deadwood.
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- Date Issued: 2003
Host-preference and density of woodrose-forming mistletoes (Loranthaceae) on savanna vegetation, South Africa
- Authors: Dzerefos, Cathy M , Witkowski, Ed T F , Shackleton, Charlie M
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181487 , vital:43738 , xlink:href="https://doi.org/10.1023/A:1023991514968"
- Description: In the Bushbuckridge region of South Africa host preference and density of two woodrose-forming mistletoes, Erianthemum dregei (Eckl. and Zeyh.) V. Tieghem and Pedistylis galpinii (Schinz ex Sprague) was quantified in relation to land-use (harvested or unharvested), rainfall (high, more than 660 or low , less than 660 mm year−1) and catenal position (top or lower slope). These two mistletoes are generalist hemi-parasites of savanna trees and shrubs occurring on 25 and 17 hosts respectively, seven of which are shared. Thirty-six percent of woody plant species recorded were found to be hosts. Although Sclerocarya birrea (A. Rich.) Hochst. comprised only 4% of woody plant density in the environment, it was the principal host for both mistletoes, accounting for 71% of total E. dregei and 42% of P. galpinii infection. Mistletoe infection relative to density of Ficus stuhlmanii, Trichilia emetica and Cassine transvaalensis indicated that these were preferential hosts to S. birrea. Mistletoe host preference was negatively correlated with host wood density. Mistletoe number per tree had a weak relationship to canopy size. Mistletoes of all size classes were denser at high rainfall relative to low rainfall sites. Interestingly, the overall mistletoe size class distribution was similar between harvested and unharvested sites. The ratio of living to dead mistletoe was 2 to 1 for E. dregei and 1.5 to 1 for P. galpinii. There are sufficient dead mistletoes in unharvested and harvested areas to satisfy present market demand. Living E. dregei predominated in harvested rather than unharvested areas suggesting that current-harvesting levels had little or no negative effect on the population. In contrast, P. galpinii was denser in unharvested areas possibly owing to its higher market value and thus higher harvesting levels.
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- Date Issued: 2003