Logic Specifications Research Articles

Not just playing: The politics of designing games for impact on anticipatory climate governance

Simulation games are increasingly popular tools for opening up future imaginaries, especially in the arena of sustainability policy-making and decision support. However, there is a lack of understanding regarding the potential power of games in anticipatory governance. We argue that the utility of simulation games in support of anticipatory climate governance can be greatly increased when game processes are consciously designed to impact present day planning and action. At the same time, game designers with the intention to support or intervene in governance and policy-making inevitably enter political arenas and bear responsibility for understanding and managing their influence at the science-policy interface. We present two case studies: a game simulating a sustainable food policy council with food system actors in Kyoto, Japan, and a game focused on the exploration and imagination of the global impacts of climate tipping points aimed at participants of the global climate negotiation community. Each case study represents a specific logic for translating game play into real-world impacts at different governance scales with distinct political implications. Based on these two case studies, we develop principles for the design and evaluation of simulation games that seek to impact anticipatory climate governance, based on five lenses: (1) purpose and positionality; (2) conceptions of the future and imaginaries; (3) beneficiaries, key stakeholders and participants; (4) the politics of game features and design; and (5) evaluation.

Live synthesis

Synthesis automatically constructs an implementation that satisfies a given logical specification. In this paper, we study the live synthesis problem, where the synthesized implementation replaces an already running system. In addition to satisfying its own specification, the synthesized implementation must guarantee a sound transition from the previous implementation. This version of the synthesis problem is highly relevant in “always-on” applications, where updates happen while the system is running. To specify the correct handover between the old and new implementation, we introduce an extension of linear-time temporal logic (LTL) called LiveLTL. A LiveLTL specification defines separate requirements on the two implementations and ensures that the new implementation satisfies, in addition to its own requirements, any obligations left unfinished by the old implementation. For specifications in LiveLTL, we show that the live synthesis problem can be solved within the same complexity bound as standard reactive synthesis, i.e., in 2EXPTIME. Our experiments show the necessity of live synthesis for LiveLTL specifications created from benchmarks of SYNTCOMP and robot control.

Characterization, verification and generation of strategies in games with resource constraints

With an increasing demand for ensuring the reliability and efficiency of distributed and interactive systems, the model-checking technique has been studied extensively, for which a game-based modeling of the system and a logical specification of the desired properties are two essential parts. Existing studies mainly focused on ideal systems that always guarantee optimal responses and have not considered several realistic aspects, for instance, the fact that actions can only be performed under sufficient resources. In this paper, we propose a game model with resource constraints and thereby a novel logic named LRC for such games. This logic enables the strategic reasoning of the likely strategies of the other participating entities and thus supports not only the characterization of the equilibrium of games with limited resources, but also strategic exploitation in multi-agent systems in which the available resources are restricted. Interesting properties of this logic are investigated, and a model-checking algorithm is presented. Being built upon the alternating-time temporal logic (ATL), LRC is shown to be more expressive than ATL without bringing additional complexity. In addition to determining the existence or absence of a collaborative strategy, we explore the generation of the team plan when a certain protocol is supposed to be followed.

Synthesis of strategies for autonomous surveillance on adversarial targets

We study the problem of synthesizing a controller for an agent with imperfect sensing and a quantitative surveillance objective, that is, an agent is required to maintain knowledge of the location of a moving, possibly adversarial target. We formulate the problem as a one-sided partial-information game with a winning condition expressed as a temporal logic specification. The specification encodes the quantitative surveillance requirement as well as any additional tasks. Solving a partial-information game typically involves transforming it into a perfect-information belief game using a belief-set construction. Such a transformation leads to a state-space explosion, rendering the belief game computationally intractable to solve for most realistic settings. We present a belief-set abstraction technique to transform the partial-information game to a provably sound abstract belief game that can be solved efficiently using off-the-shelf reactive synthesis tools. We introduce a counterexample-guided refinement approach to automatically achieve the abstraction precision sufficient to synthesize a strategy that is provably winning on the original partial-information game. We evaluate the proposed method on multiple case-studies, implemented on hardware as well as high-fidelity ROS/Gazebo simulations where the agent must respond in real-time to a human-controlled adversary.

Hierarchical multi-robot strategies synthesis and optimization under individual and collaborative temporal logic specifications

This paper presents a hierarchical framework for multi-robot temporal logic task planning. We assume that each robot has its individual task specification and the robots have to jointly satisfy a global collaborative task specification, both described in finite linear temporal logic. To reduce the overall computational complexity, a central server firstly extracts and decomposes a collaborative task sequence from the automaton corresponding to the collaborative task specification, and allocates the subtasks in the sequence to robots. The robots then synthesize their initial execution strategies based on locally constructed product automatons, which integrate task requirements of the assigned collaborative tasks and their individual task specifications. Further, to reduce robots’ wait time in collaborations, we propose a distributed execution strategy adjusting mechanism to iteratively improve the time efficiency of robots. Finally, we prove the completeness of the proposed framework under assumptions, and analyze its time complexity and optimality. Extensive simulation results verify the scalability and optimization efficiency of the proposed method.

Tribal narrative in the Syrian political universe

The following article deals with the problem of formation and functioning of tribal narratives in the political universe of Syria. The author shows how tribe narrative is structured in the form of epic narration within the framework of which different political events acquire a special logic and vested with new connotations. The tribe which comprehends political relations through the prism of this narrative, structures its communication with forces external relative to it, the state included, in a special way. The accomplished research is based both on open sources and on materials of the author’s interviews with the representatives of Hsana tribe, which he took in summer and autumn 2021. The results of the research, as it seems, could be useful for studying the general problems of tribalism and relations of tribes and state in the Middle East.

Optimality Versus Opportunity: The Recurrent Evolution of Similar Sex Determination Mechanisms.

Sex determination mechanisms vary widely across animals, but show remarkable degrees of recurrent evolution. Recurrent features of sex determination have largely been attributed to recurrent cooption of shared ancestral regulatory circuits. However, a new study on sex determination in Daphnia magna reveals both recurrent evolution of specific regulatory logic and apparently recurrent recruitment of a regulator, suggesting a role for optimization in recurrent patterns of sex determination mechanisms.

Decentralized route-planning for multi-vehicle teams to satisfy a subclass of linear temporal logic specifications

Linear temporal logic (LTL) formulae are widely used to provide high level behavioral specifications on mobile robots. We propose a decentralized route-planning method for a networked team of mobile robots to satisfy a common (global) LTL specification. The global specification is assumed to be a conjunction of multiple formulae, each of which is treated as a task to be assigned to one or more vehicles. The vehicle kinematic model consists of two modes: a hover mode and a constant-speed forward motion mode with bounded steering rate. The proposed method leverages the consensus-based bundle algorithm for decentralized task assignment, thereby decomposing the global specification into local specifications for each vehicle. We develop a new algorithm to assign collaborative tasks: those simultaneously assigned to multiple vehicles. Rewards in the proposed task assignment algorithm are computed using the so-called lifted graph, which ensures the satisfaction of minimum turn radius constraints on vehicular motion. This algorithm synchronizes the vehicles’ routes with minimum waiting durations. The proposed method is compared against a multi-vehicle task assignment algorithm from the literature, which we extend to apply for satisfying LTL specifications. The proposed route-planning method is demonstrated via numerical simulation examples and a hardware implementation on networked single-board computers.

Performance Comparison of the Conventional CMOS and MTCMOS Digital Circuits and Their Simulation

This paper focuses on the design of the conventional CMOS digital circuits and the Multi-Threshold CMOS (MTCMOS) digital circuits, which perform the specific Boolean logic function, as well as the comparison between these designing techniques by their functionality and power consummation (dissipation). The leakage of currents in integrated circuits based on CMOS logic becomes quite significant when the complementary MOS transistors are the small-device geometries (small dimensions), and this effect imposes alternative techniques that enable the designing of CMOS digital circuits with low-power dissipation, even in standby mode. One of these techniques is the design of the CMOS digital circuits with multi-threshold voltage (MTCMOS), which enables the reduction of the leakage power dissipation, as a part of the overall power dissipation in CMOS logic. Two CMOS digital circuits are designed (2-input XNOR CMOS gate and the other one is the CMOS gate that performs a complex Boolean function) based on conventional CMOS technique and multi-threshold voltage CMOS technique, and their functionality and calculation of the average overall power dissipation are tested using the Computer-Aided Design (CAD). The methodology used to achieve low power dissipation in CMOS digital circuits (MTCMOS) will be an efficient method for reducing the overall dissipation, while the high speed performance will be maintained.

An Introduction to Quantum Model Checking

Model checking is a well-established and widely adopted framework used to verify whether a given system satisfies the desired properties. Properties are usually given by means of formulas from a specific logic; there are several logics that can be used, such as CTL and LTL, which permit the expression of different types of properties on the branching-time or on the linear-time evolution of the system. In this paper, we will consider the problem of model checking quantum systems and present the solutions given in literature for solving such a problem with respect to different types of properties.

Embedded system implementation of an evolutionary algorithm for circle detection on programmable devices

Programmable devices combine powerful processing systems with a rich infrastructure of general-purpose and specific logic blocks, making it possible the efficient implementation of embedded systems to perform complex tasks by facilitating hardware acceleration of critical stages to improve their performance. Based on these characteristics, a hardware implementation of a genetic algorithm for circle detection in digital images is described in this paper. The detection system has been designed for Xilinx Zynq-7000 and Zynq UltraScale+ family devices and implemented on two low-cost development boards that reach acceleration factors of 33.12 and 37.3, respectively, when compared to the fully software implementation. Detection results from both development boards have been compared using synthetic and real images from different scenarios. The accuracy and performance achieved demonstrate the suitability of this proposal to design embedded systems with restricted size, resources and energy consumption for applications in Internet of Things, Industry 4.0 and other related paradigms.

Mean-Payoff Games with ω-Regular Specifications

Multi-player mean-payoff games are a natural formalism for modelling the behaviour of concurrent and multi-agent systems with self-interested players. Players in such a game traverse a graph, while attempting to maximise a (mean-)payoff function that depends on the play generated. As with all games, the equilibria that could arise may have undesirable properties. However, as system designers, we typically wish to ensure that equilibria in such systems correspond to desirable system behaviours, for example, satisfying certain safety or liveness properties. One natural way to do this would be to specify such desirable properties using temporal logic. Unfortunately, the use of temporal logic specifications causes game theoretic verification problems to have very high computational complexity. To address this issue, we consider ω-regular specifications. These offer a concise and intuitive way of specifying system behaviours with a comparatively low computational overhead. The main results of this work are characterisation and complexity bounds for the problem of determining if there are equilibria that satisfy a given ω-regular specification in a multi-player mean-payoff game in a number of computationally relevant game-theoretic settings.

Necessary conditions in international business research–Advancing the field with a new perspective on causality and data analysis

Many researchers in international business (IB) refer to necessity when they theorize about the relationships between different concepts. However, necessary conditions involve a specific causal logic: they represent constraints, bottlenecks, or critical factors that must be overcome for a desired outcome to exist. Usually, this logic is not fully acknowledged, neither in theoretical thinking nor in empirical research. In this paper, we demonstrate the relevance of necessary conditions in IB research and discuss how an adequate consideration of necessity logic can advance the field. Furthermore, we introduce necessary condition analysis (NCA) as a new analytical technique that identifies necessary conditions in data sets. We illustrate its application by analyzing whether certain institutional factors are necessary conditions for inward foreign direct investment. Finally, we assess the value of necessity logic and NCA as novel approaches to think about causality and to analyze data in IB.

Specification and optimal reactive synthesis of run-time enforcement shields

A run time enforcement shield is a controller which corrects the output O of a system with sporadic errors (SSE) so as to guarantee the invariance of a critical requirement. Moreover, the shield output O′ must deviate from the SSE output O “as little as possible” to maintain the quality. We give a method for logical specification of shields using logic QDDC. The specification consists of a correctness requirement REQ, a mandatory hard deviation constraint HDC, and a soft deviation constraint SDC whose satisfaction must be optimized in an H-optimal fashion. We show how a tool DCSynth implementing soft requirement guided synthesis is used for the automatic synthesis of shields from such specifications. Next, we give logical formulation of various notions of shields including Bloem's k-Stabilizing shield, Wu's Burst-error shield, as well as new EK-shield and Windowed-EK-shield. We experimentally compare the performance of the shields synthesized under these notions.

Les béatitudes du Nouveau Testament (Mt 5,3–12a ; Lc 6,20b–26) à la lumière de celles de Qumrân (4Q525 2 ii 1–6 ; 1QHa VI 13–16) et de la littérature intertestamentaire

Abstract After the finding of a list of Beatitudes in one of the Dead Sea manuscripts (4Q525 2 ii 1–6) and, especially, once the identification of the well-known expression “poor in spirit” from the Gospel of Matthew with one of the most influential works of the community who produced these manuscripts (1QHa or the Thanksgiving Hymns) has been established, a legitimate question has been debated, that is whether and in which extent it is possible to speak about the existence of a literary interdependency between these two corpora. Not only that we encounter in Matt 5,3–12a and Lk 6,20b–26 two structures of this type, but it can be legitimately addressed the point that these two series present variations, which are original and proper. With the aid of a comparative analysis with the texts of 4Q525 and 1QHa VI 13–16 we may be able to acknowledge their importance and final aim. New perspectives will emerge from the philological and theological overview, in respect to the bridges that the two lists of Beatitudes entertain. It seems that between the first century before and after Jesus Christ, a well-established literary genre proposed elaborated beatitudes and/or woes that were functioning following a specific redactional logic.

Bottom-up synthesis of recursive functional programs using angelic execution

We present a novel bottom-up method for the synthesis of functional recursive programs. While bottom-up synthesis techniques can work better than top-down methods in certain settings, there is no prior technique for synthesizing recursive programs from logical specifications in a purely bottom-up fashion. The main challenge is that effective bottom-up methods need to execute sub-expressions of the code being synthesized, but it is impossible to execute a recursive subexpression of a program that has not been fully constructed yet. In this paper, we address this challenge using the concept of angelic semantics. Specifically, our method finds a program that satisfies the specification under angelic semantics (we refer to this as angelic synthesis), analyzes the assumptions made during its angelic execution, uses this analysis to strengthen the specification, and finally reattempts synthesis with the strengthened specification. Our proposed angelic synthesis algorithm is based on version space learning and therefore deals effectively with many incremental synthesis calls made during the overall algorithm. We have implemented this approach in a prototype called Burst and evaluate it on synthesis problems from prior work. Our experiments show that Burst is able to synthesize a solution to 94% of the benchmarks in our benchmark suite, outperforming prior work.

Online video games and patient-staff power relations. A qualitative study of care and custody in forensic psychiatry.

Accessible summaryWhat is known on the subject? Frontline forensic mental health staff often face challenges when providing recovery‐orientated care, as they must balance between caring for the forensic psychiatric patient and at the same time ensuring safety and security for all other patients and staff at the ward.Research shows that balancing between care and custody in everyday clinical practice is possible, but more practical nursing studies showing ways of balancing power relations are needed to guide clinical practice.Online video games are increasingly recognized as promising new tools to promote social relations, establish competencies and re‐articulate power relations in therapeutic environments. What the paper adds to existing knowledge? This paper provides insights into how using online video gaming interventions may influence the establishment of social power relations of staff and forensic psychiatric patients. It adds to existing research by providing a conceptual way to study and understand how mental health nurses may balance between care and custody, delivering care to accommodate patients' needs without compromising safety and security at the ward.This study answers a call in current research by providing qualified knowledge regarding the use of online video gaming to build and sustain therapeutic relations in mental health care. What are the implications for practice? Our paper suggests that balancing between care and custody is possible by using online video gaming interventions in forensic psychiatry. It moreover provides practice‐close knowledge that may inspire and guide clinical mental health nurses to further develop online video gaming interventions in mental health care for the benefit of their patients. IntroductionIn recovery‐oriented care, forensic psychiatric nurses must engage in care relationships with forensic psychiatric patients (FPs) whilst focussing on ward security. Online video games (OVGs) may provide a platform for negotiating power and social relations. Studies showing how OVG interventions may influence power balances in forensic psychiatric care are needed to guide clinical practice.AimOur aim was to study how power relations were articulated between FPs and staff in an OVG intervention in a Danish forensic psychiatric ward.MethodData consist of three months of observational data and interviews with three staff members and six patients. We used sociologist Pierre Bourdieu's framework of field, power and capital to analyze data.ResultsThe OVG intervention consisted of two power fields, “in‐game” and “over‐game.” In‐game concerned the practice of gaming. Over‐game described the organization of the gaming intervention. Specific logics, skills and symbolic capitals drove power in each field.DiscussionPower in‐game was open to FPs and staff, leading to symmetric power relations. Power over‐game was open to staff only, resulting in asymmetrical power relations.Implications for practiceOnline video game interventions may facilitate power balancing in forensic psychiatry. These insights may guide the development of new OVG interventions for patients and nurses in mental health care.

Transport factor in shaping greater spaces: the Caspian and beyond

One of the dominating theories in modern international politics which in various respects explains and describes the key features of multipolar world order is the theory of greater spaces proposed by Carl Schmitt. The theory experiences its re-interpretation as many of current developments can be coherently explained by special logic. It is especially true for strategically important regions such as the Caspian region where transport factor can serve as the driver of going beyond the geographical boundaries and expanding into a greater space begin connected to adjacent states not only by geopolitical interests but by transport routes as well. The authors ground their assumption on diverse and substantial research material which includes scholarly publications on the theory of great spaces, geopolitical factors, present-day situation in the Caspian region, and statistics data of its transport potential and trade indices. Being profoundly analyzed from the point of view of various theories, Caspian politics is the reflection of diverse global, regional and national interests, while energy issues are still dominated by geopolitics. The authors point out that to follow the principles of greater space theory may turn out to be the best option for the future development of the Caspian region.

Online Motion Planning With Soft Metric Interval Temporal Logic in Unknown Dynamic Environment

Motion planning of an autonomous system with high-level specifications has wide applications. However, research of formal languages involving timed temporal logic is still under investigation. Furthermore, many existing results rely on a key assumption that user-specified tasks are feasible in the given environment. Challenges arise when the operating environment is dynamic and unknown since the environment can be found prohibitive, leading to potentially conflicting tasks where pre-specified timed missions cannot be fully satisfied. Such issues become even more challenging when considering time-bound requirements. To address these challenges, this work proposes a control framework that considers hard constraints to enforce safety requirements and soft constraints to enable task relaxation. The metric interval temporal logic (MITL) specifications are employed to deal with time-bound constraints. By constructing a relaxed timed product automaton, an online motion planning strategy is synthesized with a receding horizon controller to generate policies, achieving multiple objectives in decreasing order of priority 1) formally guarantee the satisfaction of hard safety constraints; 2) mostly fulfill soft timed tasks; and 3) collect time-varying rewards as much as possible. Another novelty of the relaxed structure is to consider violations of both time and tasks for infeasible cases. Simulation results are provided to validate the proposed approach.

Learning-Based Bounded Synthesis for Semi-MDPs With LTL Specifications

This letter proposes a learning-based bounded synthesis for a semi-Markov decision process (SMDP) with a linear temporal logic (LTL) specification. In the product of the SMDP and the deterministic K-co-Büchi automaton (dKcBA) converted from the LTL specification, we learn both the winning region of satisfying the LTL specification and the dynamics therein based on reinforcement learning and Bayesian inference. Then, we synthesize an optimal policy satisfying the following two conditions. (1) It maximizes the probability of reaching the wining region. (2) It minimizes a long-term risk for the dwell time within the winning region. The minimization of the long-term risk is done based on the estimated dynamics and a value iteration. We show that, if the discount factor is sufficiently close to one, the synthesized policy converges to the optimal policy as the number of the data obtained by the exploration goes to the infinity.