Taming Virtualization

Although the term virtualization has been around for decades, only recently has it become a buzzword in the computer systems community with the revival of virtual machines (VMs), driven by efforts in industry and academia. VMs are software entities that emulate a real machine's functionality; they execute under the control of a hypervisor that virtualizes and multiplexes low-level hardware resources. Hypervisors come in two flavors: non-hosted, which run directly on top of the hardware, and hosted, which are integrated with a host operating system (OS). The presence of a hypervisor makes VMs subject to a level of visibility and control that's hard to achieve with real machines. The small size, isolation, and mediation power of an ideal hypervisor over VMs make it an interesting candidate for a trusted computing base, with applications in security research fields such as intrusion detection, integrity protection, and malware analysis, among others.     

Taming logic

In this paper, we introduce a general technology, calledtaming, for finding well-behaved versions of well-investigated logics. Further, we state completeness, decidability, definability and interpolation results for a multimodal logic, calledarrow logic, with additional operators such as thedifference operator, andgraded modalities. Finally, we give a completeness proof for a strong version of arrow logic.Thanks to ILLC for financial and CCSOM for technical support.Supported by Hungarian National Foundation for Scientific Research grant Nos. F17452 and T16448.Supported by Hungarian National Foundation for Scientific Research grant No. T16448.     

Systems integration with reliability in mind

Device sophistication and data-processing ability continue to grow steadily and new processing devices dedicated to special functions such as speech processing or data encryption are regularly being introduced or replaced by more powerful devices. As device manufacturers extend the power and applicability of devices, new system design concepts are needed. Not only are specialist disciplines required but also the question of integration arises, a problem, all too easily overlooked. This paper looks at the problems caused by increased complexity (such as in two-sided cards on buses) and puts forward suggestions as to how to improve reliability, such as protecting the system clock and limiting the amount of parallel I/O, at least on the system card.     

Taming the PL/I syntax

Ideally the syntactic part of a PL/I compiler would be generated directly from the semi-formal definition of ANSI Standard PL/I. A practical approach to this is described, using finite state machines and an LALR parser generator. The parser uses a method due to Aoe which avoids list searching. Adapted for this method the PL/I grammar has 841 states. The parse table generator exploits the freedom to renumber states in a way that improves on previous algorithms for compacting the tables. The parser tables occupy less than 4K bytes.     

Incarnate mind

We are beings of the flesh. Our sensorimotor motor experience is the basis for the structure of our higher cognitive functions of conceptual cognition and reasoning. Consequently, our subjectivity is intimately tied up with the nature of our embodied experience. This runs directly counter to views of self-identity dominant in contemporary cognitive science. I give an account of how we ought to understand ourselves as incarnates, and how this would change our view of meaning, knowledge, reason, and subjectivity.     

Producing mind

Those who support a computationalist view of the mind tend to hold that it must apply to all aspects of mentality. This view is called computational universalism. An apparently opposed perception-phenomenal universalism-is that consciousness is at the root of all mental processes. Computationalists tend to cognitivize, or otherwise play down, phenomenal consciousness. The recent book by David Chalmers proposes one way to take both computation and phenomenal consciousness seriously. A different way is explored here, which avoids the commitment to a non-materialist ontology of consciousness in Chalmers' position. This alternative approach rejects universalism of both the computational and the phenomenal kinds. Instead a pluralistic view of mind is proposed. Cognitive and phenomenal aspects of mind are to be taken as equally fundamental and as complementary. Cognitive or productive aspects of mind have their own kind of reality which is independent of consciousness. Semantic content may well result from the combination of cognitive productivity and consciousness. The view proposed offers solutions to old problems affecting computational accounts.     

Taming the 0/1 knapsack problem with monogamous pairs genetic algorithm

This paper defines and explores a somewhat different subclass of genetic algorithm (GA) – a monogamous pairs genetic algorithm (MopGA) for solving the 0/1 knapsack problems (0/1-KP). The MopGA incorporates two important operations borrowed from social monogamy: pair bonding and infidelity at a low probability. Unlike conventional GAs, same pairs of parents (monogamous parents) are re-mated at each generation until their bonds expire. Nonetheless, this monogamy rule may be violated at the presence of infidelity. Our technique emphasizes on the thorough exploitation of the current search region via pair bonding, while allowing sufficient exploration to other unknown regions via infidelity. Consequently, MopGA is able to preserve higher population diversity by shielding offspring under the monogamous parents from population-wide selection pressure and restrictive mating strategy. As a side benefit from economical use of selection mechanism, the MopGA is computationally more efficient, especially when dealing with high-dimensionality 0/1-KPs. The empirical results on 0/1-KPs also show considerable performance in favour of the proposed methodology in terms of solution quality.     

Taming distributed system complexity through formal patterns

Many distributed systems are real-time, safety-critical systems with strong qualitative and quantitative formal requirements. They often need to be reflective and adaptive, and may be probabilistic in their algorithms and/or their operating environments. All this makes these systems quite complex and therefore hard to design, build and verify. To tame such system complexity, this paper proposes formal patterns, that is, formally specified solutions to frequently occurring distributed system problems that are generic, executable, and come with strong formal guarantees. The semantics of such patterns as theory transformations in rewriting logic is explained; and a representative collection of useful patterns is presented to ground all the key concepts and show their effectiveness.     

Implementing information systems with project teams using ethnographic-action research

Architecture, engineering, and construction (AEC) projects are characterized by a large variation in requirements and work routines. Therefore, it is difficult to develop and implement information systems to support projects. To address these challenges, this paper presents a project-centric research and development methodology that combines ethnographic observation of practitioners working in local project organizations to understand their local requirements and the iterative improvement of information systems directly on projects in small action research implementation cycles. The paper shows the practical feasibility of the theoretical methodology using cases from AEC projects in North America and Europe. The cases provide evidence that ethnographic-action research is well suited to support the development and implementation of information systems. In particular, the paper shows that the method enabled researchers on the cases to identify specific problems on AEC projects and, additionally, helped these researchers to adapt information systems accordingly in close collaboration with the practitioners working on these projects.     

Transparallel mind: classical computing with quantum power

Inspired by the extraordinary computing power promised by quantum computers, the quantum mind hypothesis postulated that quantum mechanical phenomena are the source of neuronal synchronization, which, in turn, might underlie consciousness. Here, I present an alternative inspired by a classical computing method with quantum power. This method relies on special distributed representations called hyperstrings. Hyperstrings are superpositions of up to an exponential number of strings, which—by a single-processor classical computer—can be evaluated in a transparallel fashion, that is, simultaneously as if only one string were concerned. Building on a neurally plausible model of human visual perceptual organization, in which hyperstrings are formal counterparts of transient neural assemblies, I postulate that synchronization in such assemblies is a manifestation of transparallel information processing. This accounts for the high combinatorial capacity and speed of human visual perceptual organization and strengthens ideas that self-organizing cognitive architecture bridges the gap between neurons and consciousness.     

Prescribed teams of grammars

We consider sets of grammars (calledteams) which process strings by cooperating together; a single derivation step in a team is done in such a way that each grammar in the set rewrites a symbol in the string. A cooperating grammar system with prescribed teams (CPT) consists of a finite number of teams. In a maximal rewriting mode, a team in a CPT can take a string for rewriting whenever it can make a derivation step on it; it keeps it and rewrites as long as it can, and once a string is obtained that cannot be rewritten by the team anymore it is returned and becomes available to all other teams.In this paper we investigate the power of CPT in the maximal and other rewriting modes. We establish the relationships of CPT with other models of grammars cooperating together and with various kinds of controlled grammars. We also solve some open problems from [6] and provide alternative proofs for some results from [6].The authors are indebted to Basic Research ASMICS II Working Group for supoort; the work of the first author has been also supported by the Alexander von Humboldt Foundation     

Pattern preserving path following of unicycle teams with communication delays

This paper examines the problem of pattern-preserving path following control for unicycle teams with time-varying communication delay. A key strategy used here introduces a virtual vehicle formation such that each real vehicle has a corresponding virtual vehicle as its pursuit target. Under an input-driven consensus protocol, the virtual vehicle formation is forced to stay close to the desired vehicle formation; and a novel controller design is proposed to achieve virtual leader tracking for each vehicle with constrained motion. It is shown that, by the proposed strategy, the pattern can be preserved if the formation speed is less than some computable value that decreases with increasing size of delay, and the exact desired formation pattern can be eventually achieved if this speed tends to zero.