Guarded Command Language Research Articles

National Guard Command Authority and the Black Lives Matter Protests of 2020: Domestic Security Debates for a New Generation of Military Veterans

This study explores connections between the military experiences of a new generation of War on Terror (WoT) veterans elected to the U.S. Congress and controversial policy decisions on domestic security during the Black Lives Matter (BLM) protests. WoT veterans became the largest cohort of lawmakers with common military experiences on Capitol Hill in 2020, and this article examines their engagement through two original case studies of legislative debates over command and control of the National Guard mobilization during BLM protests. Confrontations between federal law enforcement officers and BLM protestors led some WoT veterans to propose legislation to restrict executive authority over National Guard deployments, including reforms of Titles 10 and 32 of the U.S. Code and the Insurrection Act, but other WoT veterans challenged these positions. This exploratory study of events and circumstances links the timely topic of domestic security to traditional debates in the civil–military relations literature on whether veterans are more or less likely to support the use of military force and try to expand congressional oversight of presidential powers. By bridging the gap between research areas and crossing generations, this article offers lessons for past, present, and potentially future debates about the use of troops for domestic security operations.

Türk Balıkçı Gemileri Tarafından İşlenen Yasa Dışı, Kayıt Dışı, Kural Dışı (YKK) Trol İhlallerinin Değerlendirilmesi

This study analyses a highly damaging and prevalent fishing practice of trawl infringements, which is one of the crucial components of IUU fishing in Turkish waters. The raw data gathered from the Turkish Coast Guard Command (TURCG), covered 2012 – 2014 period. Data covered a total of 1040 trawl infringements, with considerable differences in trawling violations among the seas surrounding Türkiye; the Black Sea, the Sea of Marmara, the Aegean Sea, and the Mediterranean Sea. With respect to trawling infringements, the Sea of Marmara (37%) and Istanbul Strait (15%) were the hot points. The most common infringement type was trawling in a closed area (43%) and when combined with the rate of infringements on trawling during the closed season (10%), these violations accounted for 53% of spatio-temporal infringements. Regarding illegal trawling by vessel type, trawl vessels had a 44% share and non-trawlers had a share of 56%, of which included infringements by other type of fishing vessels (46%) and non-fishing vessels (10%). It was also found that infringement by vessels smaller than 12 meters in length had a share of 46%. These vessels (known as "şebeke" in Turkish), trawl illegally using small types of nets and gears in coastal waters without giving any obvious indication of fishing activity. The results of this study will be useful to policy-makers, practitioners and scientists to successfully combat trawling infringements by providing information on distribution, intensity and methods of trawl violations.

Formally Verified Samplers from Probabilistic Programs with Loops and Conditioning

We present Zar: a formally verified compiler pipeline from discrete probabilistic programs with unbounded loops in the conditional probabilistic guarded command language (cpGCL) to proved-correct executable samplers in the random bit model. We exploit the key idea that all discrete probability distributions can be reduced to unbiased coin-flipping schemes. The compiler pipeline first translates cpGCL programs into choice-fix trees, an intermediate representation suitable for reduction of biased probabilistic choices. Choice-fix trees are then translated to coinductive interaction trees for execution within the random bit model. The correctness of the composed translations establishes the sampling equidistribution theorem: compiled samplers are correct wrt. the conditional weakest pre-expectation semantics of cpGCL source programs. Zar is implemented and fully verified in the Coq proof assistant. We extract verified samplers to OCaml and Python and empirically validate them on a number of illustrative examples.

Nonlinear Program Construction and Verification Method Based on Partition Recursion and Morgan's Refinement Rules

The traditional program refinement strategy cannot be refined to an executable program, and there are issues such as low verification reliability and automation. To solve the above problems, this paper proposes a nonlinear program construction and verification method based on partition recursion and Morgan's refinement rules. First, we use recursive definition technique to characterize the initial specification. The specification is then transformed into GCL(Guarded Command Language) programs using loop invariant derivation and Morgan's refinement rules. Furthermore, VCG (Verification Condition Generator) is used in the GCL program to generate the verification condition automatically. The Isabelle theorem prover then validates the GCL program's correctness. Finally, the GCL code generates a C++ executable program automatically via the conversion system. The effectiveness of this method is demonstrated using binary tree preorder traversal program construction and verification as an example. This method addresses the problem that the construction process's loop invariant is difficult to obtain and the refinement process is insufficiently detailed. At the same time, the method improves verification process automation and reduces the manual verification workload.

Forecast combination approach with meta-fuzzy functions for forecasting the number of immigrants within the maritime line security project in Turkey.

In this study, forecasting the number of immigrants on the Turkey's maritime line for use in a national security project carried out by Turkish Government within the scope of fight against uncontrolled immigration is discussed for the first time. Handling with the immigration problem is one of the biggest concerns of Turkey as unsupervised immigration can adversely affect the demographic and economic structure of the country. Precautions are needed as the short-, medium- and long-term impacts of undetected immigrants on the country's ecosystem are unpredictable, but due to the uncertainties inherent in immigration, the cost of using government resources such as patrol vehicles to capture undocumented immigrants can be extremely high. In order to both minimize the expenditure problem and keep immigration under control by providing a proper scan, forecasting the number of immigrants on the maritime line route is seen as an important problem and studied by probabilistic and non-probabilistic models. Since the data for 2020 and 2021 could not be attained yet due to COVID-19, in order to obtain forecasts and compare actual observations for 2019, which is the primarily focus of the research in this study, the dataset of interest on the number of daily immigrants between years 2016 and 2019 is obtained from Turkish Coast Guard Command within Ministry of Interior of Republic of Turkey. To obtain the most accurate forecasts, seven distinguished forecasting methods, from simple to complex, are implemented. Then, the forecast combination approach with meta-fuzzy functions which combines all methods is proposed. Consequently, the forecasting results are acquired and evaluated by using R. The evaluation of the results is made by using widely considered measurement accuracy metric root mean square error. According to the final assessments, the proposed approach gives more accurate forecasting results for the expected number of immigrants on the Turkey's maritime line and these results become an input to the national security project.

Characterization of Fisheries Violations From the Türkiye's Mediterranean Coasts Within the Scope of Fisheries Law No. 1380

In this study, fisheries violations within the scope of the Turkish Fisheries Law No. 1380 were characterized for the Mediterranean Coasts of Türkiye. For this purpose, by taking into account the frequency and amount of the fines, the patterns of violations in terms of fishing gear, region, season, region-season and fishing gear-season by regions interactions were determined. Data were derived from the Turkish Coast Guard Command’ fisheries surveillance activities during 2014 for areas between coordinates of (36°00’00” N-29°00’00” E) and (36°00’00” N-35°45’00” E). A total of 491 violations against the Fisheries Law No. 1380 were considered. It was determined that the most violations were made by angling (23.22%) and the least by drift nets (0.4%). According to penalties amounts for the 2014, a total of $298,817 administrative fines were imposed. Trawl violations accounted for the highest total administrative fines (48.38%), while the lowest total administrative fines (0.17%) were for violations with drift nets. While the most violations were detected in Antalya region, the highest administrative fine was applied in Adana-Mersin region. According to seasons, there was a decrease in fisheries violations due to closed season measurement for fishing during summer. In terms of administrative fines, the season-region interaction was experienced the most in Adana-Mersin region during winter, and the least in Hatay-Adana region during summer. In season-region interaction, the most violations were observed in Antalya region in spring, while the least in summer in Hatay-Adana region. In interaction related to fishing gear-season by regions, it was determined that the highest number of violations and administrative fines occurred in winter during angling in Adana-Mersin region and in autumn during purse seine fishing in Hatay-Adana region. As a result, in short term, these findings could assist decision-making mechanisms for the effectiveness and efficiency of MCS (Monitoring, Control and Surveillance) system, which is an important part of fisheries management regime. In long term, these findings could also be used in a regional Decision Support System for fishery management with integrating with other elements of fisheries management regime.

Evolved model for early fault detection and health tracking in marine diesel engine by means of machine learning techniques

The Coast Guard Command, which has a wide range of duties as saving human lives, protecting natural resources, preventing marine pollution and battle against smuggling, uses diesel main engines in its ships, as in other military and commercial ships. It is critical that the main engines operate smoothly at all times so that they can respond quickly while performing their duties, thus enabling fast and early detection of faults and preventing failures that are costly or take longer to repair. The aim of this study is to create and to develop a model based on current data, to select machine learning algorithms and ensemble methods, to develop and explain the most appropriate model for fast and accurate detection of malfunctions that may occur in 4-stroke high-speed diesel engines. Thus, it is aimed to be an exemplary study for a data-based decision support mechanism.

A Study on the Training and Education of Inspectors to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated (IUU) Fishing in Turkey

The aim of this study was to examine present training conditions of inspectors and the current situation in Turkey to prevent, deter and eliminate IUU fishing within the scope of the training of qualified inspectors which was one of port states’ duties according to the PSMA to Prevent, Deter and Eliminate IUU Fishing. In Turkey, the inspectors of the Ministry of Agriculture and Forestry and the Command of Coast Guard had sufficient training according to the Annex-E of Article 17 of the PSMA to Prevent, Deter and Eliminate IUU Fishing. The trainings related to the provisions stated in the Annex-E of Article 17 of the PSMA to Prevent, Deter and Eliminate IUU Fishing should be planned or necessary studies should be carried out by the Ministry of Agriculture and Forestry for authorized institutions and organizations other than the Ministry of Agriculture and Forestry and the Coast Guard Command. Legal arrangements should be made on the training of inspectors in order to prevent IUU fishing in the Fisheries Law.

The probabilistic model checker Storm

We present the probabilistic model checker Storm. Storm supports the analysis of discrete- and continuous-time variants of both Markov chains and Markov decision processes. Storm has three major distinguishing features. It supports multiple input languages for Markov models, including the Jani and Prism modeling languages, dynamic fault trees, generalized stochastic Petri nets, and the probabilistic guarded command language. It has a modular setup in which solvers and symbolic engines can easily be exchanged. Its Python API allows for rapid prototyping by encapsulating Storm’s fast and scalable algorithms. This paper reports on the main features of Storm and explains how to effectively use them. A description is provided of the main distinguishing functionalities of Storm. Finally, an empirical evaluation of different configurations of Storm on the QComp 2019 benchmark set is presented.

Enhancing Probabilistic Model Checking with Ontologies

Probabilistic model checking (PMC) is a well-established method for the quantitative analysis of state based operational models such as Markov decision processes. Description logics (DLs) provide a well-suited formalism to describe and reason about knowledge and are used as basis for the web ontology language (OWL). We investigate how such knowledge described by DLs can be integrated into the PMC process, introducing ontology-mediated PMC. Specifically, we propose ontologized programs as a formalism that links ontologies to behaviors specified by probabilistic guarded commands, the de-facto standard input formalism for PMC tools such as Prism. Through DL reasoning, inconsistent states in the modeled system can be detected. We present three ways to resolve these inconsistencies, leading to different Markov decision process semantics. We analyze the computational complexity of checking whether an ontologized program is consistent under these semantics. Further, we present and implement a technique for the quantitative analysis of ontologized programs relying on standard DL reasoning and PMC tools. This way, we enable the application of PMC techniques to analyze knowledge-intensive systems.We evaluate our approach and implementation on amulti-server systemcase study,where different DL ontologies are used to provide specifications of different server platforms and situations the system is executed in.

Static Backward Slicing of Non-deterministic Programs and Systems

A theory of slicing non-deterministic programs and systems is developed. Non-deterministic programs and systems are represented as non-deterministic program graphs (NDPGs) that allow arbitrary non-deterministic branching to be expressed. Structural and semantic relationships that must exist between an NDPG and (1) its non-termination insensitive (weak) slices and (2) its non-termination sensitive (strong) slices are defined. Weak and strong commitment closure are introduced. These are the NDPG equivalents of being closed under non-termination sensitive and non-termination insensitive control dependence; properties defined on subsets of vertices of the equivalent deterministic structure: the control flow graph. It is proved that if a subset of the vertices of an NDPG is both data dependence closed and (weak/strong) commitment closed, then the resulting induced graph will, indeed, satisfy our structural and semantic requirements. O ( n 3 ) algorithms for computing minimal data and weak/strong commitment closed sets are given. The resulting induced graphs are thus guaranteed to be weak and strong slices, respectively. It is demonstrated, with examples, that programs written in Dijkstra's non-deterministic guarded command language (DNGCL) can be converted to NDPGs to which our slicing algorithms can then be applied. It is proved that the resulting slices (NDPGs) can always be converted back to valid DNGCL programs, highlighting the applicability of our approach to slicing at the source code level.

Conditioning in Probabilistic Programming

This article investigates the semantic intricacies of conditioning, a main feature in probabilistic programming. Our study is based on an extension of the imperative probabilistic guarded command language pGCL with conditioning. We provide a weakest precondition (wp) semantics and an operational semantics. To deal with possibly diverging program behavior, we consider liberal preconditions. We show that diverging program behavior plays a key role when defining conditioning. We establish that weakest preconditions coincide with conditional expected rewards in Markov chains—the operational semantics—and that the wp-semantics conservatively extends the existing semantics of pGCL (without conditioning). An extension of these results with nondeterminism turns out to be problematic: although an operational semantics using Markov decision processes is rather straightforward, we show that providing an inductive wp-semantics in this setting is impossible. Finally, we present two program transformations that eliminate conditioning from any program. The first transformation hoists conditioning while updating the probabilistic choices in the program, while the second transformation replaces conditioning—in the same vein as rejection sampling—by a program with loops. In addition, we present a last program transformation that replaces an independent identically distributed loop with conditioning.

A new roadmap for linking theories of programming and its applications on GCL and CSP

Formal methods advocate the crucial role played by the algebraic approach in specification and implementation of programs. Traditionally, a top-down approach (with denotational model as its origin) links the algebra of programs with the denotational representation by establishment of the soundness and completeness of the algebra against the given model, while a bottom-up approach (a journey started from operational model) introduces a variety of bisimulations to establish the equivalence relation among programs, and then presents a set of algebraic laws in support of program analysis and verification. This paper proposes a new roadmap for linking theories of programming. Our approach takes an algebra of programs as its foundation, and generates both denotational and operational representations from the algebraic refinement relation. This new approach is applied in this paper to GCL (Guarded Command Language) and CSP (Communicating Sequential Processes) to link their various semantical representations based on their algebraic semantics. • A new roadmap for linking theories of programming from program algebra. • This paper demonstrates the approach to GCL and CSP. • Varies denotational models can be derived from the program algebra. • Consistent operational semantics can be derived from the program algebra.

From model checking to equilibrium checking: Reactive modules for rational verification

Model checking is the best-known and most successful approach to formally verifying that systems satisfy specifications, expressed as temporal logic formulae. In this article, we develop the theory of equilibrium checking, a related but distinct problem. Equilibrium checking is relevant for multi-agent systems in which system components (agents) are assumed to be acting rationally in pursuit of delegated goals, and is concerned with understanding what temporal properties hold of such systems under the assumption that agents select strategies in equilibrium. The formal framework we use to study this problem assumes agents are modelled using Reactive Modules, a system modelling language that is used in a range of practical model checking systems. Each agent (or player) in a Reactive Modulesgame is specified as a nondeterministic guarded command program, and each player's goal is specified with a temporal logic formula that the player desires to see satisfied. A strategy for a player in a Reactive Modules game defines how that player selects enabled guarded commands for execution over successive rounds of the game. For this general setting, we investigate games in which players have goals specified in Linear Temporal Logic (in which case it is assumed that players choose deterministic strategies) and in Computation Tree Logic (in which case players select nondeterministic strategies). For each of these cases, after formally defining the game setting, we characterise the complexity of a range of problems relating to Nash equilibria (e.g., the computation or the verification of existence of a Nash equilibrium or checking whether a given temporal formula is satisfied on some Nash equilibrium). We then go on to show how the model we present can be used to encode, for example, games in which the choices available to players are specified using STRIPS planning operators.

Quantum Guarded-Command Language (qGCL) for Maximum Value

On a classical computer or a binary computer, calculations are done simultaneously so as to produce the equations and algorithms. The result of this research shows that to determined maximum value specified in the algorithm using quantum Guarded-Command Language (qGCl) in quantum computer. Initially determine of maximum value was construct in Djikstra’s Guarded-Command Language (GCL) which is then implemented on Zuliani’s probability Guarded-Command Language (pGCL) furthermore applying to quantum Guarded-Command Language (qGCL) for last result. Of concern here is the speed in resolving a problem or calculate problem. Due to the Quantum Computer has a Quantum Bit (qubit) and a phenomenon commonly called superposition. Keywords: GCL, pGCL, qGCL, quantum computer.

Markov Chains and Markov Decision Processes in Isabelle/HOL

This paper presents an extensive formalization of Markov chains (MCs) and Markov decision processes (MDPs), with discrete time and (possibly infinite) discrete state-spaces. The formalization takes a coalgebraic view on the transition systems representing MCs and constructs their trace spaces. On these trace spaces properties like fairness, reachability, and stationary distributions are formalized. Similar to MCs, MDPs are represented as transition systems with a construction for trace spaces. These trace spaces provide maximal and minimal expectation over all possible non-deterministic decisions. As applications we provide a certifier for finite reachability problems and we relate the denotational semantics and operational semantics of the probabilistic guarded command language. A distinctive feature of our formalization is the order-theoretic and coalgebraic view on our concepts: we view transition systems as coalgebras, we view traces as coinductive streams, we provide iterative computation rules for expectations, and we define many properties on traces as least or greatest fixed points.

Derivation of Quantum Guarded Command Language Program for Average

Has conducted research to determine the derivation of quantum guarded command language (qGCL) program for average. Initially calculation of average value was made in guaded command language (GCL) which is then implemented on a digital computer into the Pascal programming language. Furthermore GCL to calculate the average value was analyzed again to be made in the quantum guarded command language (qGCL). qGCL implementation is on a quantum computer is a future computer could perform calculations very quickly because it uses a superposition state is referred to as quantum bits (qubits). Keywords : GCL, qGCL, Quantum Computer

High-level Counterexamples for Probabilistic Automata

Providing compact and understandable counterexamples for violated system properties is an essential task in model checking. Existing works on counterexamples for probabilistic systems so far computed either a large set of system runs or a subset of the system's states, both of which are of limited use in manual debugging. Many probabilistic systems are described in a guarded command language like the one used by the popular model checker PRISM. In this paper we describe how a smallest possible subset of the commands can be identified which together make the system erroneous. We additionally show how the selected commands can be further simplified to obtain a well-understandable counterexample.

Game-Theoretic Approach to Self-Stabilizing Distributed Formation of Minimal Multi-Dominating Sets

Dominating set is a subset of nodes called dominators in a graph such that every non-dominator nodes (called dominatee) is adjacent to at least one dominator. This paper considers a more general multi-dominating problem where each node $i$ , dominator or dominatee, is required to have at least $k_i$ neighboring dominators, and different node can have different $k_i$ value. We first propose a game design toward this problem. This game is self-stabilizing (i.e., it always ends up with a legitimate state regardless of its initial configuration). The obtained result is guaranteed minimal (i.e., it contains no proper subset that is also a multi-dominating set) and Pareto optimal (we cannot increase the payoff of some player without sacrificing the payoff of any other). We then point out challenges when turning the design into a distributed algorithm using guarded commands. We present an algorithm that is proved weakly stabilizing. Simulation results show that the proposed game and algorithm produce smaller dominating sets, $k$ -dominating sets, and multi-dominating sets in various network topologies when compared with prior approaches.

Operational versus weakest pre-expectation semantics for the probabilistic guarded command language

This paper proposes a simple operational semantics of pGCL, Dijkstra’s guarded command language extended with probabilistic choice, and relates this to pGCL’s wp-semantics by McIver and Morgan. Parametric Markov decision processes whose state rewards depend on the post-expectation at hand are used as the operational model. We show that the weakest pre-expectation of a pGCL-program w.r.t. a post-expectation corresponds to the expected cumulative reward to reach a terminal state in the parametric MDP associated to the program. In a similar way, we show a correspondence between weakest liberal pre-expectations and liberal expected cumulative rewards. The verification of probabilistic programs using wp-semantics and operational semantics is illustrated using a simple running example.