Multiple dispatch in practice

Multiple dispatch uses the run time types of more than one argument to a method call to determine which method body to run. While several languages over the last 20 years have provided multiple dispatch, most object-oriented languages still support only single dispatch — forcing programmers to implement multiple dispatch manually when required. This paper presents an empirical study of the use of multiple dispatch in practice, considering six languages that support multiple dispatch, and also investigating the potential for multiple dispatch in Java programs. We hope that this study will help programmers understand the uses and abuses of multiple dispatch; virtual machine implementors optimise multiple dispatch; and language designers to evaluate the choice of providing multiple dispatch in new programming languages

Standardized contracts with swing for the market-supported procurement of energy and reserve

These are the key findings for the SC system: permits full, separate, market-based compensation for service availability and service performance (FERC Order 755); facilitates a level playing field for market participation; facilitates co-optimization of energy and reserve markets; supports forward-market trading of energy and reserve; permits service providers to offer flexible service availability; provides system operators with real-time flexibility in service usage; facilitates accurate load forecasting and following of dispatch signals; permits resources to internally manage UC and capacity constraint; permits the robust-control management of uncertain net load; eliminates the need for out-of-market payment adjustments; and reduces the complexity of market rules

Facilitating appropriate compensation of electric energy and reserve through standardized contracts with swing

Three key issues have arisen for centrally-managed wholesale electric power markets in Europe and the United States as they attempt to handle an increased penetration of variable energy resources. First, rigid definitions for energy and reserve products make it difficult to ensure appropriate compensation for important needed flexibility in start-up times, ramp-rates, power dispatch levels, and duration. Second, participation restrictions hinder the achievement of an even playing field for potential providers of flexible services. Third, reliance on out-of-market compensation for the provision of some valued services encourages strategic manipulation. This study examines the possibility of addressing these three issues through the introduction of standardized energy and reserve contracts with swing (flexibility) in their contractual terms. Concrete examples are used to demonstrate how the trading of these standardized contracts can be supported by linked forward markets in a manner that permits efficient real-time balancing of net load subject to system and reserve-requirement constraints. Comparisons with existing wholesale electric power markets are given, and key policy implications are highlighted