IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6072062
Yoseba K. Penya, C. E. Borges, I. Fernández
{"title":"Short-term load forecasting in non-residential Buildings","authors":"Yoseba K. Penya, C. E. Borges, I. Fernández","doi":"10.1109/AFRCON.2011.6072062","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6072062","url":null,"abstract":"Short-term load forecasting (STLF) has become an essential tool in the electricity sector. It has been object of vast research since energy load is known to be non-linear and, therefore, very difficult to predict with accuracy. We focus here on non-residential building STLF, an special case of STLF where weather shows smaller influence on the load than in normal scenarios and forecast models, contrary to those on the literature, are required to be simple, avoiding dull and complicated trial-and-error parametrisation or setting-up processes. Under these premises, we have used a two-step methodology comprising a classification and a adjustment steps. Since the non-linearity of the load is associated to the activity in the building, we have demonstrated that the best way to deal with it is using the work day schedule as day-type classifier. Moreover, we have evaluated a number of statistical methods and Artificial Intelligence methods to adjust the typical hourly consumption curve, concluding that an autoregressive time series suffices to fulfil the requirements, even in a 5 day-ahead horizon.","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129948919","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}
IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6072089
G. Human, G. V. Schoor, K. Uren
{"title":"Sizing of renewable energy hydrogen systems","authors":"G. Human, G. V. Schoor, K. Uren","doi":"10.1109/AFRCON.2011.6072089","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6072089","url":null,"abstract":"This paper explains the simulation and sizing optimization of renewable energy systems for hydrogen production. These systems are complex and challenging to size correctly due to the nonlinearities of the components and the stochastic nature of the sources. The same system will perform completely different at two separate sites. The simulation includes renewable energy sources, storage elements and loads. Matlab® and Simulink− are the tools utilized for the simulation and optimization. The simulation and optimization of the Renewable Energy (RenEn) system, to be constructed in Potchefstroom, South Africa, is described and some of the results obtained are discussed. The sizing of components is essential to ensure that the most efficient and cost-effective system is specified.","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131976551","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}
IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6072130
J. Machajdik, Julian Stöttinger, Ester Danelova, M. Pongratz, L. Kavicky, R. Valenti, A. Hanbury
{"title":"Providing feedback on emotional experiences and decision making","authors":"J. Machajdik, Julian Stöttinger, Ester Danelova, M. Pongratz, L. Kavicky, R. Valenti, A. Hanbury","doi":"10.1109/AFRCON.2011.6072130","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6072130","url":null,"abstract":"We present a novel lifelog system concept created to provide a human user with feedback on their conscious and unconscious emotional reactions and encourage the process of self-reflection by looking into an affective mirror. The emotion of the user is deduced from biometric data and enhanced by affective sound analysis and facial expression recognition of faces of the weares conversational partners. These high-level analyses also offer information about the social context of the user. All of the recorded data is processed using a novel modification of the spreading-activation theory which is used to model human-like associative thinking.","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130942965","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}
IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6072125
M. Mhlanga, T. Olwal, M. Mutanga, M. Adigun
{"title":"Energy optimization based path selection algorithm for IEEE 802.11s Wireless Mesh Networks","authors":"M. Mhlanga, T. Olwal, M. Mutanga, M. Adigun","doi":"10.1109/AFRCON.2011.6072125","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6072125","url":null,"abstract":"It is everyone's dream to have network connectivity anywhere at all times. This dream can only be realized provided there are feasible solutions that are put in place for the next generation of wireless works. Wireless Mesh Networks (WMNs) configures itself and because of its cost effectiveness, it is therefore seen as a solution for the next generation networks. However, this field still has a lot of limitations and the main constrain is that the energy of the nodes is very limited, especially when the network is deployed in rural areas where electricity is a scares resource. This research therefore presents an energy optimization based path selection algorithm for IEEE 802.11s WMNs which is aimed at addressing the above mentioned constrains. As a newly proposed standard specifically designed for WMN, the IEEE 802.11s does not consider energy conservation as a priority in its protocol. As a result, the main goal for this research is that paths with enough energy for transmission in the network must be selected when transmitting packets. Our simulation results obtained from the experiments prove that there is a substantial increase with regard to the network's operational time when energy is considered by the protocol used in IEEE 802.11s.","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128792262","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}
IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6071971
E. Feukeu, Karim D Djouani, A. Kurien
{"title":"Using a Greedy Algorithm for Link Adaptation in MIMO Wireless Networks","authors":"E. Feukeu, Karim D Djouani, A. Kurien","doi":"10.1109/AFRCON.2011.6071971","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6071971","url":null,"abstract":"This paper presents a Link Adaptation (LA) algorithm for Wireless Local Area Network (WLAN) IEEE 802.11n Multiple Input Multiple Output (MIMO) systems to solve the problem of wireless channel fluctuation that affect the propagation of radio signals between a transmitter and receiver. The proposed Greedy Algorithm (GA) will modify the modulation constellation size and code rate in response to the variation of the transmission medium. This Algorithm compared with the Auto-Rate-Fallback (ARF) algorithm performs better than the ARF approach in terms of throughput, packed loss, elapsed time and transmission efficiency.","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123191692","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}
IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6072121
A. Maffei, Hakan Akilliuglu, P. Neves, J. Ferreira, M. Onori
{"title":"Emerging Behavior as driver for the sustainability of a modular, “skills-centric” production system","authors":"A. Maffei, Hakan Akilliuglu, P. Neves, J. Ferreira, M. Onori","doi":"10.1109/AFRCON.2011.6072121","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6072121","url":null,"abstract":"The current main challenge for the future production system lies in the correct integration of the issues related to sustainability and to agility. The “Evolvable Paradigm” addresses this concern with a new way of engineering the whole production system. The concept of Skill is declined as common denominator between the definitions of manufacturing process and manufacturing equipment. Each production module holds some of the skills that compose the process definition and it is endowed with the necessary intelligence to come together with the other modules in an organized society. This work introduces the approach adopted in the IDEAS project (Instantly Deployable Evolvable Assembly System) to cope with the above mentioned requirement through the presented paradigm. While fully featured and described IDEAS mechatronic architecture allows rapid reconfiguration of the system, the issue of sustainability is targeted by the open definition of the concepts of skill and skills interaction. The result of skill aggregation is hereby called Emergent Behavior and in the proposed model it can be seen as the main driver for the sustainable use of the system","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121290918","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}
IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6072113
S. Zerawa, Klaus Pollhammer, T. Turek
{"title":"Simplifying routine tasks using contactless smartcards","authors":"S. Zerawa, Klaus Pollhammer, T. Turek","doi":"10.1109/AFRCON.2011.6072113","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6072113","url":null,"abstract":"Routine tasks are identified as a key-area to develop assistive systems. A new concept of a secure, flexible, decentralized, multi-user and multi-application approach for such systems is introduced. With the help of radio-frequency identification (RFID) smartcards users are provided with a new possibility of assistance in their daily tasks. Recommendations for a specific control decision are provided to users, based on previous decisions made in the same application context. The higher the level of routine, the better the recommendations can be presented to the user. The authors derive a generic system model and present a possible implementation based on Java RFID smartcards.","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121468724","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}
IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6072013
V. Musara, W. T. Ireeta, L. Wu, A. Leitch
{"title":"The impact of a high differential group delay section on the output state of polarization of propagating light","authors":"V. Musara, W. T. Ireeta, L. Wu, A. Leitch","doi":"10.1109/AFRCON.2011.6072013","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6072013","url":null,"abstract":"Research to date has shown that high differential group delay (HiDGD) sections along an optical fiber network link are the major contributors to PMD. PMD has deleterious effects on propagating optical signals. In this paper, we show the effect a HiDGD section has on the output state of polarization (SOP) of propagating light. Experimental results in this paper show a reduction in the range of the output SOP spread with an increase in the DGD of the HiDGD section to a given asymptote (a minimum) i.e. when HiDGD ≥ 35ps. However, the output SOP spread and its asymptote solely depends on the location of the HiDGD section along the fiber link length. A small output SOP spread over the entire wavelength scan covers a few polarization states on the Poincaré sphere and vice versa for a large output SOP spread. The small output SOP spread over the entire wavelength range (50 nm in steps of 0.3 nm for this study) is an indicator that the polarization capabilities of optical telecommunication signals are restricted to minute SOPs.","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121620356","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}
IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6072073
Javier Moreno, J. Wenninger, Jan Haase, C. Grimm
{"title":"Energy profiling technique for network-level energy optimization","authors":"Javier Moreno, J. Wenninger, Jan Haase, C. Grimm","doi":"10.1109/AFRCON.2011.6072073","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6072073","url":null,"abstract":"This work presents an energy profiling technique to optimize energy consumption in networks, with special focus in wireless sensor networks, where energy consumption is usually a major constraint. The approach aims to organize data obtained from power simulation in order to provide useful information to designers at high level abstraction layers, so that they are able to observe the impact of different design decisions, and therefore optimize their designs in terms of energy. Other energy profiling techniques deal only with local scope profiling, in order to optimize the node architecture. However, the energy profiling technique proposed here takes into account network-wide information expanding the scope of energy profiling to energy aware network design and optimization. Finally, the approach is further developed and its possibilities are explored by implementing on a wireless sensor network simulator and using it to optimize energy consumption at the network level in a pilot scenario.","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122955002","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}
IEEE Africon '11Pub Date : 2011-11-10DOI: 10.1109/AFRCON.2011.6072162
E. Tkacz, P. Kostka, Zbigniew Budzianowski, Wojciech Oleksy
{"title":"Continuous representation of unevenly sampled signals - An application to the analysis of heart rate variability","authors":"E. Tkacz, P. Kostka, Zbigniew Budzianowski, Wojciech Oleksy","doi":"10.1109/AFRCON.2011.6072162","DOIUrl":"https://doi.org/10.1109/AFRCON.2011.6072162","url":null,"abstract":"Various methods for the continuous representation of unevenly sampled physiological signals, especially of heart rate and heart rate variability have been published over the past two decades. Due to the mathematical difficulties of analyzing unevenly spaced event series or unevenly sampled signals, all of the previously described techniques are impeded by some severe limitations which result from either representing the signal based on an assumed and often insufficient physiological model of signal generation, or from simplifications in the selected signal processing tools. Though the described methods have their merits and allow sufficient description of heart rate in some special applications, there has been no systematic investigation into a continuous representation of unevenly sampled physiological signals which is free from any limitations or simplifying assumptions and which would allow an objective comparison of the known methods and the determination of the respective errors in order to decide which technique is the best suited for a specific application. In this paper a continuous representation of the point event series describing the temporal sequence of heart beats is presented which does not impose any limiting assumptions on the data analysis. The results obtained were validated through simulations in both time and frequency domains, and compared with the established techniques to allow the determination of errors at the specific times where the heart beats occur, as well as within the intervals between these sample points.","PeriodicalId":125684,"journal":{"name":"IEEE Africon '11","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122194150","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}