Christof Weinhardt

Cloud Computing – A Classification, Business Models, and Research Directions

Lately, a new computing paradigm has emerged: “Cloud Computing”. It seems to be promoted as heavily as the “Grid” was a few years ago, causing broad discussions on the differences between Grid and Cloud Computing. The first contribution of this paper is thus a detailed discussion about the different characteristics of Grid Computing and Cloud Computing. This technical classification allows for a well-founded discussion of the business opportunities of the Cloud Computing paradigm. To this end, this paper first presents a business model framework for Clouds. It subsequently reviews and classifies current Cloud offerings in the light of this framework. Finally, this paper discusses challenges that have to be mastered in order to make the Cloud vision come true and points to promising areas for future research.

Business Models in the Service World

The authors provide a criteria catalogue to characterize cloud computing and their own Cloud Business Ontology Model to classify current product offerings and pricing models.

The Montreal Taxonomy for Electronic Negotiations

Research in the domain of electronic negotiations is a rather new and very interdisciplinary field, which gains more and more attention due to the industry hype and momentum regarding electronic commerce and electronic markets. Negotiations in a narrow sense (not taking into account simple forms such as “hit and take”) have been identified as an advantageous coordination mechanism for the interaction of buyers and sellers in electronic markets that transcend the selling of commodities or uniform goods. Hence, support for negotiations may become a critical success factor for electronic markets, especially regarding the recent failures of many industrial ventures. This paper presents the Montreal Taxonomy, which allows not only for the exact characterisation and comparison of a broad variety of electronic negotiation designs and systems, ranging from auctions to bilateral bargaining tables, but could also lead towards a more structured approach for the design of electronic negotiations.

Trading grid services - a multi-attribute combinatorial approach

Abstract The Grid is a promising technology for providing access to distributed high-end computational capabilities. Thus, computational tasks can be performed spontaneously by other resources in the Grid that are not under the user’s control. However, one of the key problems in the Grid is deciding which jobs are to be allocated to which resources at what time. In this context, the use of market mechanisms for scheduling and allocating Grid resources is a promising approach toward solving these problems. This paper proposes an auction mechanism for allocating and scheduling computer resources such as processors or storage space which have multiple quality attributes. The mechanism is evaluated according to its economic and computational performance as well as its practical applicability by means of a simulation.

A Market Mechanism for Energy Allocation in Micro-CHP Grids

Achieving a sustainable level of energy production and consumption is one of the major challenges in our society. This paper contributes to the objective of increasing energy efficiency by introducing a market mechanism that facilitates the efficient matching of energy (i.e. electricity and heat) demand and supply in micro energy grids. More precisely we propose a combinatorial double auction mechanism for the allocation and pricing of energy resources that especially takes the specific requirements of energy producers and consumers into account. We describe the potential role of decentralized micro energy grids and their coupling to the large scale power grid. Furthermore we introduce an emergency fail over procedure that keeps the micro energy grid stable even in cases where the auction mechanism fails. As the underlying energy allocation problem itself is NP-hard, we derive a fast heuristic for finding efficient supply and demand allocations. In addition we show the applicability of this approach through numerica.

Charging Strategies for Battery Electric Vehicles: Economic Benchmark and V2G Potential

This paper benchmarks the economic benefits of a smart charging and a vehicle-to-grid (V2G) operating strategy of an electric vehicle (EV) against a zero-intelligence charging strategy in a simulation-based analysis. Smart charging optimizes the timing of EV charging, while V2G additionally allows for selling electricity to the energy market. The strategies internalize the wear on energy storage equipment. The simulation builds on over 11 400 empirical driving profiles from a German mobility panel and applies technical specifications of three currently available EVs. This allows for a realistic analysis of the applicability of smart charging and V2G as well as the extent to which EVs are capable to fulfill current driving needs. Results show that smart charging strategies will reduce charging cost on average by more than 32% in all analyzed cases. V2G could provide additional revenue for EV owners with shorter trip patterns while reducing electricity cost for others.

Improving Electric Vehicle Charging Coordination Through Area Pricing

Meeting charging demands of large electric vehicle fleets will raise electrical load significantly and may pose challenges for todays power system. Appropriate coordination of electric vehicle charging can reduce these threats. Acknowledging the interdependency between the transportation and the power system created by electric vehicles, we develop a charging coordination model based on German mobility data. We extend the prior work by explicitly accounting for both the temporal and the spatial dimension. We are thus able to analyze the loads from price-based EV fleet charging while at the same time accounting for distribution grid constraints. Furthermore, we propose a heuristic charging strategy based on limited trip and price information. Our results show that the sole use of time-based electricity prices for the coordination of electric vehicle charging produces high load spikes independent of the charging strategies and power levels. These peaks are induced by simultaneous charging activity and may cause stability problems within distribution grids in residential areas. To mitigate these load spikes, we introduce a spatial price component that reflects local capacity utilization. These local prices induce both a temporal and spatial shift of charging activity that mitigates the load spikes.

Understanding auction fever: a framework for emotional bidding

Auction fever is a multifaceted phenomenon that is frequently observed in both traditional and Internet auctions. In order to gain a better understanding of its causes, we develop a conceptual framework to analyze emotions in auctions, which is based on an exhaustive literature review. The framework integrates rational calculus with emotional aspects and suggests that emotional processing is triggered at three different stages of an auction: First, the economic environment can affect a bidder’s level of perceived competition and thus influence the bidding strategy prior to the auction. Second, auction events may have ramifications on the bidder’s emotional state during the auction due to previous investments or perceived ownership. Third, past auction outcomes may impact future bidding behavior through emotions such as the joy of winning or loser regret. Auction fever, eventually, is a phenomenon that results from the interplay of these emotional processes and causes a bidder to deviate from an initially chosen bidding strategy.

A Framework for Commercial Grids—Economic and Technical Challenges

This paper argues that the technology of Grid computing has not yet been adopted in commercial settings due to the lack of viable business models. While in academia Grid technology has already been taken up, the sharing approach among non for-profit organizations is not suitable for enterprises. In this paper, the idea of a Grid market is taken up to overcome this Grid adoption gap. We propose a framework for building up a Grid market and identifies the associated economic and technical challenges. Based on this framework, we identify a catalogue of possible market mechanisms which offer a promising fit to the Grid environment’s characteristics and which may thus help to carry the idea of Grid markets from theory to practice.

Market-based pricing in grids: On strategic manipulation and computational cost

Grid technologies and the related concepts of utility computing and cloud computing enable the dynamic sourcing of computer resources and services, thus allowing enterprises to cut down on hardware and software expenses and to focus on key competencies and processes. Resources are shared across administrative boundaries, e.g. between enterprises and/or business units. In this dynamic and inter-organizational setting, scheduling and pricing become key challenges. Market mechanisms show promise for enhancing resource allocation and pricing in grids. Current mechanisms, however, are not adequately able to handle large-scale settings with strategic users and providers who try to benefit from manipulating the mechanism. In this paper, a market-based heuristic for clearing large-scale grid settings is developed. The proposed heuristic and pricing schemes find an interesting match between scalability and strategic behavior.