Reducing Conservatism in Analysis of Networked Control Systems Using Order Constraints

This paper deals with the analysis of the stability of networked control systems (NCS). In NCS, the signal transmission between the plant and the controller is done through a communication network. Usually, this data transmission faces packet delay and dropout. Two types of NCS modeling for networks with packet dropout and one type of modeling for networks with packet delays are introduced. These models are of discrete-time switched linear types and there may be constraints on the order of the subsystems’ occurrence. The analysis will be conservative if these constraints are not taken into account. It is shown that by considering these constraints, the stability analysis will be less conservative. Both deterministic and stochastic analyses are considered and compared.

PENENTUAN JENIS FUNGSI BASIS RADIAL DALAM DUAL RECIPROCITY BOUNDARY ELEMENT METHOD

Problems involving modified Helmholtz equation are considered in this paper. To solve the problem numerically, dual reciprocity boundary element method (DRBEM) is employed. Some stage have been passed, using reciprocal relation to approximate boundary integral and domain integral in modified Helmholtz equation . Until, linear equation system are obtained in matrix form. MATLAB is used to calculate the solutions of Solutions of are compared between the exact solution and the numerical solution of modified Helmholtz equation. The numerical results are based on the using of three types of radial basis function to approximate domain integral, such as polinomial, poliharmonik spline and linear types. The solutions show that the polinomial and poliharmonik spline types are more stable and approach to exact solution than linear types.

Resourceful Program Synthesis from Graded Linear Types

Linear types provide a way to constrain programs by specifying that some values must be used exactly once. Recent work on graded modal types augments and refines this notion, enabling fine-grained, quantitative specification of data use in programs. The information provided by graded modal types appears to be useful for type-directed program synthesis, where these additional constraints can be used to prune the search space of candidate programs. We explore one of the major implementation challenges of a synthesis algorithm in this setting: how does the synthesis algorithm efficiently ensure that resource constraints are satisfied throughout program generation? We provide two solutions to this resource management problem, adapting Hodas and Miller’s input-output model of linear context management to a graded modal linear type theory. We evaluate the performance of both approaches via their implementation as a program synthesis tool for the programming language Granule, which provides linear and graded modal typing.

Reverse AD at Higher Types: Pure, Principled and Denotationally Correct

We show how to define forward- and reverse-mode automatic differentiation source-code transformations or on a standard higher-order functional language. The transformations generate purely functional code, and they are principled in the sense that their definition arises from a categorical universal property. We give a semantic proof of correctness of the transformations. In their most elegant formulation, the transformations generate code with linear types. However, we demonstrate how the transformations can be implemented in a standard functional language without sacrificing correctness. To do so, we make use of abstract data types to represent the required linear types, e.g. through the use of a basic module system.

Monocyclic Peptides: Types, Synthesis and Applications

: Peptides are considered to be appropriate tools in various biological fields. They can be primarily used for the rational design of bioactive molecules. They can act as ligands in the development of targeted therapeutics as well as diagnostics, can be used in the design of vaccines or can be employed in agriculture. Peptides can be classified in two broad structural classes: linear and cyclic peptides. Monocyclic peptides are a class of polypeptides with one macrocyclic ring that bears advantages, such as more selective binding and uptake by the target receptor, as well as higher potency and stability compared to linear types. This paper provides an overview of the categories, synthesis methods and various applications of cyclic peptides. The various applications of cyclic peptides include their use as pro-apoptotic and anti-microbial agents, their application as targeting ligands in drug delivery and diagnostic agents, as well as agricultural and therapeutics applications that are elaborated and discussed in this paper.

Modeling of the natural and technogenic risks dynamics

A general view of the model of risk assessment in the natural-technogenic system (NTS), considering the effects of natural and technogenic factors, is considered. The general solution of the system of differential equations describing the model is found. Two examples of the application of the model for the case of functionally similar natural and technogenic impacts are analyzed: (i) linear effects resulting in catastrophic seismic events; (ii) parabolic impacts that lead to creep, karst-deformation, subsidence and landslide processes. In addition, two new models of the dynamics of risks arising in a TCP under the influence of dangerous natural and technogenic factors are described. The presented models differ from each other in the types of effects: in the first model, they consider jointly parabolic (reflecting threats, the intensity of which gradually decreases with distance from the epicenter) and linear types of effects (reflecting suddenly arising threats), in the second model, the analysis of such types of impacts as parabolic and hyperbolic (reflecting threats whose intensity decreases sharply over time) is carried out. It is concluded that, on the basis of the considered models, it is possible to accurately describe almost any type of combined natural and technological impact and also make a special “atlas” of complex effects on the NTS for preventive “playing” of various situations and developing effective counteraction to emerging dangers from the departments of the Ministry of Emergencies and other structures.

Modular Inference of Linear Types for Multiplicity-Annotated Arrows

Bernardy et al. [2018] proposed a linear type system $$\lambda ^q_\rightarrow $$ λ → q as a core type system of Linear Haskell. In the system, linearity is represented by annotated arrow types $$A \rightarrow _m B$$ A → m B , where m denotes the multiplicity of the argument. Thanks to this representation, existing non-linear code typechecks as it is, and newly written linear code can be used with existing non-linear code in many cases. However, little is known about the type inference of $$\lambda ^q_\rightarrow $$ λ → q . Although the Linear Haskell implementation is equipped with type inference, its algorithm has not been formalized, and the implementation often fails to infer principal types, especially for higher-order functions. In this paper, based on OutsideIn(X) [Vytiniotis et al., 2011], we propose an inference system for a rank 1 qualified-typed variant of $$\lambda ^q_\rightarrow $$ λ → q , which infers principal types. A technical challenge in this new setting is to deal with ambiguous types inferred by naive qualified typing. We address this ambiguity issue through quantifier elimination and demonstrate the effectiveness of the approach with examples.

Gradual session types

Session types are a rich type discipline, based on linear types, that lifts the sort of safety claims that come with type systems to communications. However, web-based applications and microservices are often written in a mix of languages, with type disciplines in a spectrum between static and dynamic typing. Gradual session types address this mixed setting by providing a framework which grants seamless transition between statically typed handling of sessions and any required degree of dynamic typing. We propose Gradual GV as a gradually typed extension of the functional session type system GV. Following a standard framework of gradual typing, Gradual GV consists of an external language, which relaxes the type system of GV using dynamic types; an internal language with casts, for which operational semantics is given; and a cast-insertion translation from the former to the latter. We demonstrate type and communication safety as well as blame safety, thus extending previous results to functional languages with session-based communication. The interplay of linearity and dynamic types requires a novel approach to specifying the dynamics of the language.