AFRICON 2007最新文献_第4页

Solar thermal energy systems in camping sites - project solcamp 露营地的太阳能热能系统。solcamp项目

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401582

R. Pašičko, M. B. Vrhovčak, Z. Tomsic

引用次数: 0

Implementation of 220 kV in-service insulator performance test tower in Namibia 纳米比亚220千伏在役绝缘子性能试验塔的实施

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401631

W. Vosloo, F. Engelbrecht, N. Heger, J. Holtzhausen

引用次数: 4

An adjusted ARIMA model for internet traffic 互联网流量的调整ARIMA模型

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401554

H.M.A. El Hag, S. Sharif

{"title":"An adjusted ARIMA model for internet traffic","authors":"H.M.A. El Hag, S. Sharif","doi":"10.1109/AFRCON.2007.4401554","DOIUrl":"https://doi.org/10.1109/AFRCON.2007.4401554","url":null,"abstract":"Traditional time series models such as ARIMA models have been proven to be inadequate for modelling traffic exhibiting long-range dependance. In this paper we present a new model the adjusted ARIMA model for modelling long-range dependant Internet traffic. The AARIMA model is suggested to give a quick and simple way to model Internet traffic by retaining all the properties of the ARIMA models while capturing the self- similarity. We use the Box-Jenkins methodology as a frame work for our modelling procedure. We construct our model by building the best ARIMA model possible for a trace and then adding our adjustment to obtain the equivalent AARIMA model. We show that the AARIMA model shows an evident improvement over the ARIMA model using several goodness of fit criteria, our main goodness of fit criteria is the ability to capture the Hurst parameter of the original trace being modeled. The model should not underestimate the Hurst parameter and any overestimation should be less than or equal to 20% of H parameter of the measured trace. The adjusted ARIMA model is shown to accurately predict Internet traffic for up to one hour in advance. The adjustment we propose to the ARIMA model is by introducing a feedback term made up of the first difference of the series being modeled. We used four Hurst parameter estimators to measure the self- similarity of the measured traces and both the AARIMA and ARIMA models for all measured traces. For all the estimators used the AARIMA was found to capture the long-range dependence irrespective of estimator used. We used the adjusted ARIMA model to predict three public domain internet traffic traces namely a Bellcore internet wide area network external traffic trace (length 35 hours), a Bellcore Internet Wide Area Network \"purple cable\" trace (length half an hour) and a MPEG-1 compressed video traffic trace (length half an hour). We show that for the public domain traces the AARIMA model gives values of H parameter which are more accurate than those given by the ARIMA model.","PeriodicalId":112129,"journal":{"name":"AFRICON 2007","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116596615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 24

Example of undervoltage load shedding implementation 欠压减载实现实例

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401446

M. Klarić, I. Kuzle, S. Tesnjak

引用次数: 11

On performance of residue number system coded differential space-time-frequency coding 余数系统编码空时频差分编码的性能研究

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401439

R. Akol

引用次数: 0

On-line monitoring of the refraction index of air for ultra-precise length measurements in the nano-world 空气折射率的在线监测，用于纳米领域的超精密长度测量

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401484

O. Cíp, Z. Buchta, F. Petrů, J. Lazar

{"title":"On-line monitoring of the refraction index of air for ultra-precise length measurements in the nano-world","authors":"O. Cíp, Z. Buchta, F. Petrů, J. Lazar","doi":"10.1109/AFRCON.2007.4401484","DOIUrl":"https://doi.org/10.1109/AFRCON.2007.4401484","url":null,"abstract":"In the production of semiconductor microchips, nano-components like MEMS, in the field of optical lithography, an even more precise length measuring devices are necessary for a reliable fabrication. In a lot of cases we can find modern high- resolution laser interferometers. They use a wavelength of the laser beam like a fundamental unit of length. If the interferometers measure distances in atmospheric conditions, the absolute value of the laser wavelength fluctuates in linear form with a refraction index of air. It causes a distortion of the measured values, so that, the repeatability of controlled dimensions can be degraded. To elimination of this influence the on-line monitoring of the value of the refraction index of air is very necessary. On basis of knowledge of the index, the wavelength of the laser beam used in the distance measurement can be corrected to true value. Because the technique of direct measurement of the refraction index are not solved sufficiently now, we put together a new method that uses a special design of an optical resonator working like a laser refractometer. The possible changes of the refraction index of air have the influence to the optical length of the resonator. Principle of monitoring of the length changes of the resonator, down-conversion of the optical frequency changes of a tunable laser into the radio-frequency domain, and experimental verification of the method with any others are key parts of the presented work.","PeriodicalId":112129,"journal":{"name":"AFRICON 2007","volume":"3 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131436321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

802.11 Mesh mode provides rural coverage at low cost 802.11 Mesh模式以低成本覆盖农村地区

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401647

K. Naidoo, R. Sewsunker

引用次数: 13

Formal management of object behavior with statechart DNA 使用状态图DNA对对象行为进行正式管理

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401522

B. de Leeuw, A. Hoogewijs

引用次数: 2

Emotional intelligence: a crucial human resource management ability for engineering project managers in the 21st century 情商:21世纪工程项目经理的关键人力资源管理能力

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401530

M. Barry, Y. du Plessis

{"title":"Emotional intelligence: a crucial human resource management ability for engineering project managers in the 21st century","authors":"M. Barry, Y. du Plessis","doi":"10.1109/AFRCON.2007.4401530","DOIUrl":"https://doi.org/10.1109/AFRCON.2007.4401530","url":null,"abstract":"Human resource management and the corresponding soft-skills or abilities are pivotal to project management success. One of the measures of these soft-skills, used in recent years, is the concept of emotional intelligence. Emotional intelligence (EI) is the capacity to grasp, appreciate and discerningly manage emotions in relationship to oneself and others. This research focused on exploring the notion of emotional intelligence and its importance as ability for project managers in the 21st century. The first step was to explore the literature and develop a construct of emotional intelligence that could be applicable to project managers. The second step was to determine whether emotional intelligence, as per said construct, is perceived to be important for project managers. A web-based survey questionnaire was developed and distributed to 5444 project stakeholders across the globe, of which 395 (7.25%) responses were unspoiled. The findings from the statistical data analyses indicate that almost 90% of participants are of the opinion that emotional intelligence is a critical ability for project managers and the four factor construct of emotional intelligence is applicable to project managers, especially in the 21st century.","PeriodicalId":112129,"journal":{"name":"AFRICON 2007","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133317991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14

The design of an electro-optic control circuit for photonic packet switching applications 一种用于光子分组交换的电光控制电路的设计

AFRICON 2007 Pub Date : 2007-12-12 DOI: 10.1109/AFRCON.2007.4401449

J. S. van der Merwe, R. Geldenhuys, S. Yu, K. Thakulsukanant, Z. Wang, N. Chi

{"title":"The design of an electro-optic control circuit for photonic packet switching applications","authors":"J. S. van der Merwe, R. Geldenhuys, S. Yu, K. Thakulsukanant, Z. Wang, N. Chi","doi":"10.1109/AFRCON.2007.4401449","DOIUrl":"https://doi.org/10.1109/AFRCON.2007.4401449","url":null,"abstract":"We demonstrate the design and experimental implementation of an electro-optic control system that is used to detect the arrival of packets at the optical switch input, process the headers of the packets, and control switching according to the header content for both fixed and variable length packets. We also demonstrate the flexibility of the electro-optic crosspoint switch for implementation in a photonic packet switching (PPS) network. Furthermore, contention resolution is demonstrated in the electro-optic crosspoint switch by detecting packets at the input ports and controlling the switch operation accordingly. By incorporating this control system into the crosspoint switch it is possible to route contending packets to a re-circulating fiber delay line and control the switch output in a flexible manner for any type of traffic depending on the applied switching algorithm. The experiments are carried out with 155 Mbit/s headers and 10 Gbit/s payloads transmitted on a single wavelength with a guard time of 12.8 ns between header and payload. PPS with bit error rate (BER) less than 10-9 is demonstrated. Error free contention resolution is shown with the main signal degradation being from the switch cell attenuation and amplifier ASE that can be alleviated by eliminating fiber-to-fiber transmission loss in the crosspoint.","PeriodicalId":112129,"journal":{"name":"AFRICON 2007","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131924633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0