Impact Assessment of Hypothesized Cyberattacks on Interconnected Bulk Power Systems

The first-ever Ukraine cyberattack on power grid has proven its devastation by hacking into their critical cyber assets. With administrative privileges accessing substation networks/local control centers, one intelligent way of coordinated cyberattacks is to execute a series of disruptive switching executions on multiple substations using compromised supervisory control and data acquisition (SCADA) systems. These actions can cause significant impacts to an interconnected power grid. Unlike the previous power blackouts, such high-impact initiating events can aggravate operating conditions, initiating instability that may lead to system-wide cascading failure. A systemic evaluation of "nightmare" scenarios is highly desirable for asset owners to manage and prioritize the maintenance and investment in protecting their cyberinfrastructure. This survey paper is a conceptual expansion of real-time monitoring, anomaly detection, impact analyses, and mitigation (RAIM) framework that emphasizes on the resulting impacts, both on steady-state and dynamic aspects of power system stability. Hypothetically, we associate the combinatorial analyses of steady state on substations/components outages and dynamics of the sequential switching orders as part of the permutation. The expanded framework includes (1) critical/noncritical combination verification, (2) cascade confirmation, and (3) combination re-evaluation. This paper ends with a discussion of the open issues for metrics and future design pertaining the impact quantification of cyber-related contingencies

Cascading verification initiated by switching attacks through compromised digital relays

Attackers are able to enumerate all devices and computers within a compromised substation network. Digital relays deployed in the substation are the devices with IP addresses that can be discovered in the process of trial-and-error search. This paper is concerned with studies of cyberattacks manipulating digital relays to disruptively disconnect the associated breakers. The plausible enumeration of such disruptive attack for each relay in a substation is verified with the dynamic simulation studies with the special protection system for frequency, voltage, and rotor angle stability. A pertinent approach with smaller scale contingency analysis results is proposed to reduce the enormous computation burden. The devised enumeration reduction method is evaluated using IEEE test cases. The proposed method provides an extensive enumeration strategy that can be used by utility engineers to identify the pivotal relays in the system and can be further strengthened with security protection

First shark from the late Devonian (Frasnian) gogo formation, Western Australia sheds new light on the development of tessellated calcified cartilage

Background: Living gnathostomes (jawed vertebrates) comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans) and Osteichthyes (bony fishes including tetrapods). Most of the early chondrichthyan (‘shark’) record is based upon isolated teeth, spines, and scales, with the oldest articulated sharks that exhibit major diagnostic characters of the group—prismatic calcified cartilage and pelvic claspers in males—being from the latest Devonian, c. 360 Mya. This paucity of information about early chondrichthyan anatomy is mainly due to their lack of endoskeletal bone and consequent low preservation potential. Methodology/Principal Findings: Here we present new data from the first well-preserved chondrichthyan fossil from the early Late Devonian (ca. 380–384 Mya) Gogo Formation Lägerstatte of Western Australia. The specimen is the first Devonian shark body fossil to be acid-prepared, revealing the endoskeletal elements as three-dimensional undistorted units: Meckel’s cartilages, nasal, ceratohyal, basibranchial and possible epibranchial cartilages, plus left and right scapulocoracoids, as well as teeth and scales. This unique specimen is assigned to Gogoselachus lynnbeazleyae n. gen. n. sp.Conclusions/Significance: The Meckel’s cartilages show a jaw articulation surface dominated by an expansive cotylus, and a small mandibular knob, an unusual condition for chondrichthyans. The scapulocoracoid of the new specimen shows evidence of two pectoral fin basal articulation facets, differing from the standard condition for early gnathostomes which have either one or three articulations. The tooth structure is intermediate between the ‘primitive’ ctenacanthiform and symmoriiform condition, and more derived forms with a euselachian-type base. Of special interest is the highly distinctive type of calcified cartilage forming the endoskeleton, comprising multiple layers of nonprismatic subpolygonal tesserae separated by a cellular matrix, interpreted as a transitional step toward the tessellated prismatic calcified cartilage that is recognized as the main diagnostic character of the chondrichthyans

COOPERATIVE GARBAGE COLLECTORS USING SMART POINTERS IN THE C++ PROGRAMMING LANGUAGE

This research proposes to modify the C++ programming language to make it easier to define reliable, type-safe, user-defined, cooperative garbage collectors using smart-pointer classes. The major changes: -allow smart pointers to act as "this" pointers in member functions, -require the compiler to emit warnings when dangerous uses of smart pointers are detected, -restrict the use of some compiler temporaries, and -modify the rules governing the conversion of one smart-pointer class to another. Most of the proposed changes have been implemented in a C++ compiler. The modified compiler was used to implement a list-processing benchmark that uses a simple garbage collector and smart-pointer classes. The benchmark shows that the run-time cost of using smart pointers is non-trivial and suggestions are made that should improve this performance substantially. An algorithm is also described that coordinates the activities of many collectors in an application, in order to reclaim cycles of objects that span garbage-collected heaps. The main conclusion of this research is that it is practical to modify the C++ language to support reliable, type-safe user-defined, cooperative garbage collectors that use smart pointer classes.We are currently acquiring citations for the work deposited into this collection. We recognize the distribution rights of this item may have been assigned to another entity, other than the author(s) of the work.If you can provide the citation for this work or you think you own the distribution rights to this work please contact the Institutional Repository Administrator at [email protected]

A PROPOSAL FOR A COOPERATIVE, GARBAGE COLLECTED "C" PROGRAMMING LANGUAGE

This report identifies issues which arise when extending the C language to cooperate with a garbage collector managing a garbage collected heap. Adding a garbage collected heap to C is intended to increase programmer productivity by reducing the complexity of applications which use dynamically allocated memory. A mechanism is known for garbage collection in C applications which do not cooperate with the collector, but this mechanism is relatively expensive. This report proposes modifications to the C language which will allow it to cooperate with a garbage collector. The proposal modifies the syntax and semantics of C very little, and the extension degrades the performance of only those expressions which manipulate references to the garbage collected heap. The proposal was partially implemented in a compiler for a C-like language whose target machine was a FORTH-like virtual machine.We are currently acquiring citations for the work deposited into this collection. We recognize the distribution rights of this item may have been assigned to another entity, other than the author(s) of the work.If you can provide the citation for this work or you think you own the distribution rights to this work please contact the Institutional Repository Administrator at [email protected]

DESIGN ALTERNATIVES FOR A COOPERATIVE GARBAGE COLLECTOR FOR THE C++ PROGRAMMING LANGUAGE

Currently, conservative garbage collectors for C++ are the collectors which enjoy the most use. While prototype cooperative collectors have been written for C++, the language does not support either a type-safe or a reliable cooperative collector. This report examines design alternatives for adding support to the C++ programming language for cooperative garbage collection and discusses in detail alternatives which provide language support for user defined cooperative collectors. This report concludes that no C++ collector supporting multiple storage classes can be completely cooperative. Furthermore, language-recognized parameterized smart pointer types show promise both for supporting user defined collectors and for supporting persistent object caches, distributed object stores and other kinds of storage managers. Further research is needed however, in the areas of type inquiry and the coordination of multiple storage managers, before any parameterized smart pointer proposal can be completed. This discussion is based on experiments with a compacting, cooperative collector in existing implementations of C++. The changes to the language discussed in this report have not yet been implemented.We are currently acquiring citations for the work deposited into this collection. We recognize the distribution rights of this item may have been assigned to another entity, other than the author(s) of the work.If you can provide the citation for this work or you think you own the distribution rights to this work please contact the Institutional Repository Administrator at [email protected]

Cooperative garbage collectors using smart pointers in the C++ programming language

Bibliography: p. 97-103

A SURVEY OF MEMORY MANAGEMENT TECHNIQUES FOR LISP ON SMALL MACHINES

This paper surveys the field of memory management techniques suitable for use in the LISP language and identifies those techniques most suited to LISP in the context of small, real memory workstations using stock CPU's. The best performing techniques include pointer reversal, phantom stacks, CDR-encoding and a hybrid incrementally compacting collector.We are currently acquiring citations for the work deposited into this collection. We recognize the distribution rights of this item may have been assigned to another entity, other than the author(s) of the work.If you can provide the citation for this work or you think you own the distribution rights to this work please contact the Institutional Repository Administrator at [email protected]

Cyber-Based Contingency Analysis

© 2016 IEEE. Microprocessor-based relays protecting against fault current have revolutionized power automation industry. The leverage using commercially available information communication technologies has been the currency for future cyberinfrastructure deployment, which enables plausible electronic manipulation that can affect system operation. The bus differential protection has been recognized as one of the most critical protection schemes, if compromised, that would disconnect a large number of components within a substation. A hypothesized substation outage is the worst case scenario of intrusion attack events. This paper proposes an impact analysis of critical cyber assets in substations that capture historical load and topology conditions. This is to identify critical substations and other \u27nightmare\u27 hypothesized combinations for security protection planning. The proposed metrics of attack scenarios incorporate electronic instrumentation in relation to the physical system for impact and dependency evaluation. Combinatorial verification of these hypothesized events based on the proposed reverse pyramid model (RPM) is validated using IEEE 30-and 118-bus systems