Peer-Daten-Management-Systeme (PDMS) bestehen aus einer hochdynamischen Menge heterogener, autonomer Peers. Die Peers beantworten Anfragen einerseits gegen lokal gespeicherte Daten und reichen sie andererseits nach einer Umschreibung anhand von Schema-Mappings an benachbarte Peers weiter. Solche aufgrund fehlender zentraler Komponenten eigentlich hoch- flexiblen Systeme leiden bei zunehmender Anzahl von Peers unter erheblichen Effi- zienzproblemen. Die Gründe hierfür liegen in der massiven Redundanz der Pfade im Netzwerk der Peers und im Informationsverlust aufgrund von Projektionen entlang von Mapping-Pfaden. Anwender akzeptieren in hochskalierten Umgebungen zum Datenaustausch in vielen Anwendungsszenarien Konzessionen an die Vollständigkeit der Anfrageergebnisse. Unser Ansatz sieht in der Vollständigkeit ein Optimierungsziel und verfolgt einen Kompromiß zwischen Nutzen und Kosten der Anfragebearbeitung. Hierzu schlagen wir mehrere Strategien für Peers vor, um zu entscheiden, an welche Nachbar-Peers Anfragen weitergeleitet werden. Peers schließen dabei Mappings von der Anfragebearbeitung aus, von denen sie ein geringes Verhältnis von Ergebnisgröße zu Kosten, also geringe Effizienz erwarten. Als Basis dieser Schätzungen wenden wir selbstadaptive Histogramme über die Ergebniskardinalität an und weisen nach, daß diese in dieser hochdynamischen Umgebung ausreichende Genauigkeit aufweisen. Wir schlagen einen Kompromiß zwischen der Nutzung von Anfrageergebnissen zur Anpassung dieser Metadaten-Statistiken und der Beschneidung von Anfrageplänen vor, um den entsprechenden Zielkonflikt aufzulösen. Für eine Optimierungsstrategie, die das für die Anfragebearbeitung verwendete Zeit-Budget limitiert, untersuchen wir mehrere Varianten hinsichtlich des Effizienzsteigerungspotentials. Darüber hinaus nutzen wir mehrdimensionale Histogramme über die Überlappung zweier Datenquellen zur gezielten Verminderung der Redundanz in der Anfragebearbeitung. / Peer data management systems (PDMS) consist of a highly dynamic set of autonomous, heterogeneous peers connected with schema mappings. Queries submitted at a peer are answered with data residing at that peer and by passing the queries to neighboring peers. PDMS are the most general architecture for distributed integrated information systems. With no need for central coordination, PDMS are highly flexible. However, due to the typical massive redundancy in mapping paths, PDMS tend to be very inefficient in computing the complete query result as the number of peers increases. Additionally, information loss is cumulated along mapping paths due to selections and projections in the mappings. Users usually accept concessions on the completeness of query answers in large-scale data sharing settings. Our approach turns completeness into an optimization goal and thus trades off benefit and cost of query answering. To this end, we propose several strategies that guide peers in their decision to which neighbors rewritten queries should be sent. In effect, the peers prune mappings that are expected to contribute few data. We propose a query optimization strategy that limits resource consumption and show that it can drastically increase efficiency while still yielding satisfying completeness of the query result. To estimate the potential data contribution of mappings, we adopted self-tuning histograms for cardinality estimation. We developed techniques that ensure sufficient query feedback to adapt these statistics to massive changes in a PDMS. Additionally, histograms can serve to maintain statistics on data overlap between alternative mapping paths. Building on them, redundant query processing is reduced by avoiding overlapping areas of the multi-dimensional data space.

Datenbanksysteme verwenden Indexstrukturen, um Suchanfragen zu beschleunigen. Im Laufe der letzten Jahre haben Forscher verschiedene Ansätze zur Indexierung von Datenbanktabellen im Hauptspeicher entworfen. Hauptspeicherindexstrukturen versuchen möglichst häufig Daten zu verwenden, die bereits im Zwischenspeicher der CPU vorrätig sind, anstatt, wie bei traditionellen Datenbanksystemen, die Zugriffe auf den externen Speicher zu optimieren. Die meisten vorgeschlagenen Indexstrukturen für den Hauptspeicher beschränken sich jedoch auf Punktabfragen und vernachlässigen die ebenso wichtigen Bereichsabfragen, die in zahlreichen Anwendungen, wie in der Analyse von Genomdaten, Sensornetzwerken, oder analytischen Datenbanksystemen, zum Einsatz kommen. Diese Dissertation verfolgt als Hauptziel die Fähigkeiten von modernen Hauptspeicherdatenbanksystemen im Ausführen von Bereichsabfragen zu verbessern. Dazu schlagen wir zunächst die Cache-Sensitive Skip List, eine neue aktualisierbare Hauptspeicherindexstruktur, vor, die für die Zwischenspeicher moderner Prozessoren optimiert ist und das Ausführen von Bereichsabfragen auf einzelnen Datenbankspalten ermöglicht. Im zweiten Abschnitt analysieren wir die Performanz von multidimensionalen Bereichsabfragen auf modernen Serverarchitekturen, bei denen Daten im Hauptspeicher hinterlegt sind und Prozessoren über SIMD-Instruktionen und Multithreading verfügen. Um die Relevanz unserer Experimente für praktische Anwendungen zu erhöhen, schlagen wir zudem einen realistischen Benchmark für multidimensionale Bereichsabfragen vor, der auf echten Genomdaten ausgeführt wird. Im letzten Abschnitt der Dissertation präsentieren wir den BB-Tree als neue, hochperformante und speichereffziente Hauptspeicherindexstruktur. Der BB-Tree ermöglicht das Ausführen von multidimensionalen Bereichs- und Punktabfragen und verfügt über einen parallelen Suchoperator, der mehrere Threads verwenden kann, um die Performanz von Suchanfragen zu erhöhen. / Database systems employ index structures as means to accelerate search queries. Over the last years, the research community has proposed many different in-memory approaches that optimize cache misses instead of disk I/O, as opposed to disk-based systems, and make use of the grown parallel capabilities of modern CPUs. However, these techniques mainly focus on single-key lookups, but neglect equally important range queries. Range queries are an ubiquitous operator in data management commonly used in numerous domains, such as genomic analysis, sensor networks, or online analytical processing. The main goal of this dissertation is thus to improve the capabilities of main-memory database systems with regard to executing range queries. To this end, we first propose a cache-optimized, updateable main-memory index structure, the cache-sensitive skip list, which targets the execution of range queries on single database columns. Second, we study the performance of multidimensional range queries on modern hardware, where data are stored in main memory and processors support SIMD instructions and multi-threading. We re-evaluate a previous rule of thumb suggesting that, on disk-based systems, scans outperform index structures for selectivities of approximately 15-20% or more. To increase the practical relevance of our analysis, we also contribute a novel benchmark consisting of several realistic multidimensional range queries applied to real- world genomic data. Third, based on the outcomes of our experimental analysis, we devise a novel, fast and space-effcient, main-memory based index structure, the BB- Tree, which supports multidimensional range and point queries and provides a parallel search operator that leverages the multi-threading capabilities of modern CPUs.

Die parallele Anfragebearbeitung für relationale Datenbankmanagementsysteme (RDBMS) ist wegen ihrer unterschiedlichen Arten der Ausführungsparallelität und den Eigenschaften der zugrunde liegenden parallelen Architektur ein äusserst komplexes Problem. Systemänderungen zur Laufzeit der Anfrage können zusätzlich ein dynamisches Verhalten der ausführenden Komponenten erfordern, um eine nahezu optimale Antwortzeit zu gewährleisten. Diese Arbeit stellt einen neuen, flexiblen Ansatz für die Optimierung und Abarbeitung von komplexen Anfragen vor, der besonders die dynamische Optimierung berücksichtigt. Insbesondere werden in der Arbeit folgende Teile präsentiert: 1. die Architektur eines neuen, verteilt-kooperierenden Komponentensystems beeinflusst von agenten-orientierten Konzepten; 2. der Entwurf und die Realisierung einer neuen Kommunikationsinfrastruktur für die identifizierten Systemkomponenten; 3. der Entwurf und die Implementierung eines flexiblen Anfrageoptimierers mit einem neuen, zufallsbasierten Algorithmus; und 4. der Entwurf und die Realisierung einer parallel arbeitenden Ausführungskomponente unter besonderer Berücksichtigung der dynamischen Anfrageoptimierung. Bei der Entwicklung der Konzepte standen neben den spezifischen Anforderungen für RDBMS besonders die Konfigurierbarkeit und die Erweiterbarkeit des verteilten Systems im Vordergrund. / Parallel query evaluation for relational database management systems (RDBSM) still remains a challenging problem. Modern systems must show near optimal performance in spite of running in a heterogeneous hardware environment, exploiting different ways of parallelism and dealing with unpredictable system load. This thesis paper presents a dynamic and flexible system addressing the issues of optimization and evaluation of relational queries for a distributed and dynamic environment. In particular, this work consists of: 1) the architecture of a distributed system which was inspired by the concepts of software agents, 2) the architecture and the implementation of a communication infrastructure for the system components, 3) the architecture and the implementation of a new query optimization algorithm, and 4) the concept and the implementation of a new query evaluation engine for parallel execution, which enables runtime optimization of queries. Furthermore, the design supports the extension and the configuration of the system and its components.

Event Stream Processing (ESP) Systeme überwachen kontinuierliche Datenströme, um benutzerdefinierte Queries auszuwerten. Die Herausforderung besteht darin, dass die Queryverarbeitung zustandsbehaftet ist und die Anzahl von Teilübereinstimmungen mit der Größe der verarbeiteten Events exponentiell anwächst. Die Dynamik von Streams und die Notwendigkeit, entfernte Daten zu integrieren, erschweren die Zustandsverwaltung. Erstens liefern heterogene Eventquellen Streams mit unvorhersehbaren Eingaberaten und Queryselektivitäten. Während Spitzenzeiten ist eine erschöpfende Verarbeitung unmöglich, und die Systeme müssen auf eine Best-Effort-Verarbeitung zurückgreifen. Zweitens erfordern Queries möglicherweise externe Daten, um ein bestimmtes Event für eine Query auszuwählen. Solche Abhängigkeiten sind problematisch: Das Abrufen der Daten unterbricht die Stream-Verarbeitung. Ohne eine Eventauswahl auf Grundlage externer Daten wird das Wachstum von Teilübereinstimmungen verstärkt. In dieser Dissertation stelle ich Strategien für optimiertes Zustandsmanagement von ESP Systemen vor. Zuerst ermögliche ich eine Best-Effort-Verarbeitung mittels Load Shedding. Dabei werden sowohl Eingabeeevents als auch Teilübereinstimmungen systematisch verworfen, um eine Latenzschwelle mit minimalem Qualitätsverlust zu garantieren. Zweitens integriere ich externe Daten, indem ich das Abrufen dieser von der Verwendung in der Queryverarbeitung entkoppele. Mit einem effizienten Caching-Mechanismus vermeide ich Unterbrechungen durch Übertragungslatenzen. Dazu werden externe Daten basierend auf ihrer erwarteten Verwendung vorab abgerufen und mittels Lazy Evaluation bei der Eventauswahl berücksichtigt. Dabei wird ein Kostenmodell verwendet, um zu bestimmen, wann welche externen Daten abgerufen und wie lange sie im Cache aufbewahrt werden sollen. Ich habe die Effektivität und Effizienz der vorgeschlagenen Strategien anhand von synthetischen und realen Daten ausgewertet und unter Beweis gestellt. / Event stream processing systems continuously evaluate queries over event streams to detect user-specified patterns with low latency. However, the challenge is that query processing is stateful and it maintains partial matches that grow exponentially in the size of processed events. State management is complicated by the dynamicity of streams and the need to integrate remote data. First, heterogeneous event sources yield dynamic streams with unpredictable input rates, data distributions, and query selectivities. During peak times, exhaustive processing is unreasonable, and systems shall resort to best-effort processing. Second, queries may require remote data to select a specific event for a pattern. Such dependencies are problematic: Fetching the remote data interrupts the stream processing. Yet, without event selection based on remote data, the growth of partial matches is amplified. In this dissertation, I present strategies for optimised state management in event pattern detection. First, I enable best-effort processing with load shedding that discards both input events and partial matches. I carefully select the shedding elements to satisfy a latency bound while striving for a minimal loss in result quality. Second, to efficiently integrate remote data, I decouple the fetching of remote data from its use in query evaluation by a caching mechanism. To this end, I hide the transmission latency by prefetching remote data based on anticipated use and by lazy evaluation that postpones the event selection based on remote data to avoid interruptions. A cost model is used to determine when to fetch which remote data items and how long to keep them in the cache. I evaluated the above techniques with queries over synthetic and real-world data. I show that the load shedding technique significantly improves the recall of pattern detection over baseline approaches, while the technique for remote data integration significantly reduces the pattern detection latency.

In higher education institutions, virtual learning systems (VLSs) have been adopted, and are becoming increasingly popular among educators. However, despite this ubiquity of VLS use, there has not been widespread change in pedagogic practice to take advantage of the functionality afforded by VLSs. Knowledge of the actual usage of e-learning systems is limited in terms of what specific feature sets are deemed useful, and how this influences system usage. VLSs have a suite of tools with associated functions/features and properties, as well as non-functional system characteristics. In addition, these systems incorporate pedagogic features to cater for online teaching. Educators in higher education, who are the chief agents of e-learning, are confounded by system-related, pedagogic, organisational, user difference and demographic factors that influence VLS usage. Virtual learning system usage involves system feature usage extent and frequency, total system usage and usage clusters. The aim of this study is to develop a model representing the factors that influence usage of VLSs in higher education. The links between system usage and system-related factors, pedagogic factors, organisational factors, user-difference and demographic factors is researched. This research incorporated a literature study, a pilot study, interviews and surveys. A case study research strategy was combined with a mixed methods research design. The results of the qualitative analysis was triangulated with the findings of the quantitative analysis and compared to the findings of the literature study. The study was conducted at two residential higher education institutions (HEI), namely, University of KwaZulu-Natal and Durban University of Technology. The main contribution of this study is the Virtual Learning System Usage Model (VLSUM) representing the factors that influence VLS usage in residential higher education institutions. The proposed VLSUM is based on the empirical results of this study. VLSUM can be used by managers of educational technology departments and instructional designers to implement interventions to optimize usage. The constructs of VLSUM confirmed existing theories, replicated and synthesised theories from different fields, and extended existing models to produce a new model for understanding the factors that influence VLS usage in higher education. / Computing / D. LITT. et. Phil. (Information Systems)

A continuous increase in demands from the utility grid and traction applications have steered public attention toward the integration of energy storage (ES) and hybrid ES (HESS) solutions. Modern technologies are no longer limited to batteries, but can include supercapacitors (SC) and flywheel electromechanical ES well. However, insufficient control and algorithms to monitor these devices can result in a wide range of operational issues. A modern day control platform must have a deep understanding of the source. In this dissertation, specialized modular Energy Storage Management Controllers (ESMC) were developed to interface with a variety of ES devices. The EMSC provides the capability to individually monitor and control a wide range of different ES, enabling the extraction of an ES module within a series array to charge or conduct maintenance, while remaining storage can still function to serve a demand. Enhancements and testing of the ESMC are explored in not only interfacing of multiple ES and HESS, but also as a platform to improve management algorithms. There is an imperative need to provide a bridge between the depth of the electrochemical physics of the battery and the power engineering sector, a feat which was accomplished over the course of this work. First, the ESMC was tested on a lead acid battery array to verify its capabilities. Next, physics-based models of lead acid and lithium ion batteries lead to the improvement of both online battery management and established multiple metrics to assess their lifetime, or state of health. Three unique HESS were then tested and evaluated for different applications and purposes. First, a hybrid battery and SC HESS was designed and tested for shipboard power systems. Next, a lithium ion battery and SC HESS was utilized for an electric vehicle application, with the goal to reduce cycling on the battery. Finally, a lead acid battery and flywheel ES HESS was analyzed for how the inclusion of a battery can provide a dramatic improvement in the power quality versus flywheel ES alone.

The radio astronomy and space geodesy scientific instrumentation of the Hartebeesthoek Radio Astronomy Observatory (HartRAO) in Gauteng, South Africa, generate large volumes of data. Additional large data volumes will be generated by new geodesy instruments that are currently under construction and implementation, including a lunar laser ranging (LLR) system, seismic and meteorological systems and a Very Long Baseline Interferometry (VLBI) global observing system (VGOS) radio telescope. The existing HartRAO data management and storage system is outdated, incompatible and has limited storage capacity. This necessitates the design of a new geodetic research data management system (GRDMS). The focus of this dissertation is on providing a contextual framework for the design of the new system, including criteria, characteristics, components, an infrastructure architectural model and data structuring and organisation. An exploratory research methodology and qualitative research techniques were applied. Results attained from interviews conducted and literature consulted indicates a gap in the literature regarding the design of a data management system, specifically for geodetic data generated by HartRAO instrumentation. This necessitates the development of a conceptual framework for the design of a new GRDMS. Results are in alignment with the achievement of the research questions and objectives set for this study. / Information Science / M.A. (Information Science)

In higher education institutions, virtual learning systems (VLSs) have been adopted, and are becoming increasingly popular among educators. However, despite this ubiquity of VLS use, there has not been widespread change in pedagogic practice to take advantage of the functionality afforded by VLSs. Knowledge of the actual usage of e-learning systems is limited in terms of what specific feature sets are deemed useful, and how this influences system usage. VLSs have a suite of tools with associated functions/features and properties, as well as non-functional system characteristics. In addition, these systems incorporate pedagogic features to cater for online teaching. Educators in higher education, who are the chief agents of e-learning, are confounded by system-related, pedagogic, organisational, user difference and demographic factors that influence VLS usage. Virtual learning system usage involves system feature usage extent and frequency, total system usage and usage clusters. The aim of this study is to develop a model representing the factors that influence usage of VLSs in higher education. The links between system usage and system-related factors, pedagogic factors, organisational factors, user-difference and demographic factors is researched. This research incorporated a literature study, a pilot study, interviews and surveys. A case study research strategy was combined with a mixed methods research design. The results of the qualitative analysis was triangulated with the findings of the quantitative analysis and compared to the findings of the literature study. The study was conducted at two residential higher education institutions (HEI), namely, University of KwaZulu-Natal and Durban University of Technology. The main contribution of this study is the Virtual Learning System Usage Model (VLSUM) representing the factors that influence VLS usage in residential higher education institutions. The proposed VLSUM is based on the empirical results of this study. VLSUM can be used by managers of educational technology departments and instructional designers to implement interventions to optimize usage. The constructs of VLSUM confirmed existing theories, replicated and synthesised theories from different fields, and extended existing models to produce a new model for understanding the factors that influence VLS usage in higher education. / Computing / D. LITT. et. Phil. (Information Systems)

In the world in which we live today, information and communication technology (ICT) has proliferated in all spheres of society, including in the corporate, social and academic arenas. Within these arenas ICT has made noteworthy contributions. In the academic space, which is the focus of this study, ICT has made a significant contribution to the communication and consultation between students and higher education institution staff. One such example has been the emergence of learning management systems (LMSs) in higher education institutions, both locally and globally, with LMSs providing higher education institutions with several possibilities as regards facilitating the online teaching and learning process. Nevertheless, research has shown that there is underutilisation of LMSs throughout the world. The purpose of this study, therefore, was to investigate the utilisation of LMSs in an open and distance learning (ODL) institution in South Africa to ascertain whether they are being used to their full potential. / Educational Studies / M. Ed. (Adult Education)

Thesis (MBA (Business Management))--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: Socially, politically and economically, Cape Town Central City is one of the most important urban areas in South Africa. Apart from the fact that it is historically and culturally the oldest and most cosmopolitan city in South Africa, the Central Business District (CBD)accommodates about 240 000 commuters every day, generates more than R133 million in rates every year, constitutes over 20% of the economic turnover of the entire metropolitan area and provides over a quarter of all jobs in the Cape Town metropolitan area. Major challenges facing the Cape Town central precinct in the mid-1990s included growing vacancies, the capital flight to decentralised business nodes, the loss of value in buildings and the municipal rate base, the decline in building refurbishments, the shortage of parking, badly managed public open spaces and a rise in general crime rates. Through the transformation and revitalisation of the Central City, traditional economic sectors, such as the financial and business services sector, have been retained while the retail sector, tourism, information and communication technologies, and the creative industries have all shown growth. The formation of the Cape Town Partnership (CTP) and the Central City Improvement District (CID) gave the Central City an opportunity to combat the decay. The successful implementation of quality urban management systems has led to the development of new buildings and the refurbishment / redevelopment or recycling of approximately 160 buildings and public open spaces. Vacancies have decreased while the cumulative investment in the Central City since 2000 amounted to approximately R14 billion. This includes the capital value of leases, new developments, upgrades and renewals of buildings, and purchasing buildings for investment purchases. Since the last Municipal Valuation, the value of property in the Central City has increased significantly. As a result, the municipal rates base of the area also increased. With the implementation of the new General Valuation in July 2007, the city increased its annual revenue in the form of rates by more than 65%. Improved property fundamentals, sustainable rentals, increases in new developments and greater diversity are the result of the increased value of properties in the Central City. Office rentals increased steadily since the first quarter of 1995, while capitalisation rates decreased dramatically since the first quarter of 2003. Vacancy rates also decreased over the same period. Retail rentals are still in an upward phase since 1999 and the forecast by property economist Erwin Rode states that office rentals should continue to increase over the next five years with an average of approximately 14,6%. The last major challenge facing the Central City is the ability of the different spheres of government to work together as a unit and in turn with civil society organisations, NGOs and the private sector to ensure the success of the Cape Town Metropolitan area. / AFRIKAANSE OPSOMMING: Die sentrale stad van Kaapstad is een van die belangrikste stedelike gebiede in Suid-Afrika wat maatskaplike, politieke en ekonomiese kwessies betref. Buiten die feit dat dit histories en kultureel die oudste en mees kosmopolitaanse stad in Suid-Afrika is, word die Sentrale Sakegebied (SSG) elke dag deur sowat 240 000 pendelaars besoek en genereer dit elke jaar meer as R133 miljoen in munisipale belasting. Die SSG verteenwoordig ook 20% van die ekonomiese omset van die hele metropolitaanse gebied en verskaf meer as 'n kwart van al die werkgeleenthede in die Kaapstadse metropolitaanse gebied. Die uitdagings wat die Kaapstadse sentrale gebied in die mid-1990's ervaar het, sluit in toenemende leegstande, kapitaalvlug na gedesentraliseerde sakenodusse, waardeverlies in geboue en in munisipale belastingbasis, afname in gebou-opkappings, tekort aan parkering, openbare oop ruimtes wat swak bestuur word, en 'n toename in algemene misdaadsyfers. Deur die transformasie en heroplewering van die sentrale stadsgebied kon tradisionele ekonomiese sektore soos die finansiële en sakedienstesektor behou word terwyl die kleinhandelsektor, toerisme, inligting- en kommunikasietegnologie, en die kreatiewe bedryfsrigtings almal groei aangetoon het. Die ontstaan van die Kaapstadse Vennootskap (KV) en die sentrale stadsverbeteringsdistrik (SSVD) het aan die sentrale stad 'n geleentheid gebied om die verval om te swaai. Die suksesvolle implementering van stedelike bestuurstelsels van gehalte het tot die ontwikkeling van nuwe geboue en die opknapping / herontwikkeling of herbenutting van sowat 160 geboue en openbare oop ruimtes gelei. Leegstande het aansienlik gedaal terwyl die kumulatiewe belegging in die sentrale stad sedert 2000 op sowat R14 miljard beraam word. Dit sluit in die kapitaalwaarde van huurkontrakte, nuwe ontwikkelings, opgraderings en die opknapping van geboue, en die koop van geboue vir beleggingsdoeleindes. Die waarde van eiendom in die sentrale stad het sedert die vorige Munisipale Waardasie beduidend toegeneem. As gevolg hiervan het die munisipale belastingbasis van die gebied ook toegeneem. Met die implementering van die nuwe Algemene Waardasie in Julie 2007 het die stad sy jaarlikse inkomste in die vorm van belasting met meer as 65% verhoog. Die toename in die waarde van eiendom in die sentrale stad het gelei tot verbeterde eiendomsfundamentele, volhoubare huurkontrakte, 'n toename in nuwe ontwikkelings en groter diversiteit. Kantoorhuur het sedert die eerste kwartaal van 1995 bestendig toegeneem terwyl kapitalisasiekoerse sedert die eerste kwartaal van 2003 dramaties gedaal het. Leegstandsyfers het ook oor dieselfde tydperk gedaal. Kleinhandelhuur is sedert 1999 steeds in 'n opswaaifase en die eiendomsekonoom Erwin Rode voorspel dat kantoorhuur oor die volgende vyf jaar gemiddeld met sowat 14,6% sal toeneem. Die laaste groot uitdaging vir sentrale stad is die vermoë van die verskillende sfere van die regering om as 'n eenheid saam te werk, en ook om met die burgerlike gemeenskapsorganisasies, NRO's en die private sektor saam te werk om die sukses van die Kaapstadse metropolitaanse gebied te verseker.