Abstract This paper investigates empirically the competition effects on procurement costs for Europe Aid funded supply tenders in countries benefiting from EU Pre-accession (IPA) and Neighbourhood (ENI) financial instruments. We use a dataset created curated by us tender dossiers published Aid. determine reference price each procured lot based contracting authority’s requirement to establish pa...

The Theme of this special issue is software sustainability—the capability of software systems to endure different types of change over their lifetimes. In our special features, you’ll find a discussion of technical solutions aimed at supporting software changes via robust architectures. While the technical side is undoubtedly important, discussions of software sustainability often get tangled u...

Many models have been proposed to explain the opinion formation in a group of individuals; most of these models study the opinion propagation as the interaction between nodes/agents in a social network. The opinion formation is a very complex process and a realistic model should also take into account the important feedbacks that the opinions of the agents have on the structure of the social ne...

The walras algorithm calculates competitive equilibria via a distributed tatonnement-like process, in which agents submit single-good demand functions to market-clearing auctions. The algorithm is asynchronous and decentralized with respect to both agents and markets, making it suitable for distributed implementation. We present a formal description of this algorithm, and prove that it converge...

We present assume-guarantee model checking, a novel technique for verifying correctness properties of loosely-coupled multithreaded software systems. Assume-guarantee model checking verifies each thread of a multithreaded system separately by constraining the actions of other threads with an automatically inferred environment assumption. Separate verification of each thread allows the enumerati...

Rely-guarantee is a well-established approach to reasoning about concurrent programs that use parallel composition. However, parallel composition is not how concurrency is structured in real systems. Instead, threads are started by ‘fork’ and collected with ‘join’ commands. This style of concurrency cannot be reasoned about using rely-guarantee, as the life-time of a thread can be scoped dynami...

Reasoning about concurrent programs can be very difficult due to the possibility of interference. The fundamental insight of Rely-Guarantee thinking is that developing concurrent designs can only be made compositional if the development method offers ways to record and reason about the interference that is inherent in concurrency. The original presentation of rely-guarantee rules used keywords ...

PT Lookman Djaja is a trucking delivery service company that has been serving Business-to-Business (B2B) consumers, especially in Java, Sumatra, Bali, Lombok to NTB. To be able exist for more than 35 years highly competitive industry certainly quite demanding, not mention very challenging. However, it undeniable affected from both outside and within the industry. The economic downturn since COV...

The problem of handling adaptivity in data analysis, intentional or not, permeates a variety of fields, including test-set overfitting in ML challenges and the accumulation of invalid scientific discoveries. We propose a mechanism for answering an arbitrarily long sequence of potentially adaptive statistical queries, by charging a price for each query and using the proceeds to collect additiona...