2,060 research outputs found
Ck-Log, A Calculus for Knowledge Processing in Logic
No full textThis paper introduces the principal concepts in the organization and operation of the logic based knowledge processing system, called CK-LOG (A Calculus for Knowledge in Logics). CK-LOG uses the frame based system MDS (the Meta Description System) for knowledge representation and for modeling world states. It uses an inference engine based on Natural Deduction for stating and solving problems. As a knowledge processing system CK-LOG has several capabilities, which are new to the technology of knowledge representation systems: CK-LOG has special facilities to represent and reason about actions and their time dependencies. Actions that occur in a world state may create or destroy objects in the world or modify their properties, or prevent or support other actions. The effects of actions are described in CK-LOG using modal operators like CREATE, DESTROY, PREVENT, SUPPORT, KEEP, etc. These operator expressions are also used to represent and reason about possible worlds that the actions might lead to. Most significantly, CK-LOG is a logic-based knowledge processing system, just as PROLOG is logic based programming system. CK-LOG uses a three valued logical system with truth values T (true),? (Unknown) and F (false) to build partial models of world states, and the two valued logic's system of T and F in its theorem proving System. The use of the three valued logical system in its models of world states enables CK-LOG to do problem solving in the context of incomplete information about world states. The theorem proving system of CK-LOG uses a variant of the calculus of sequents first proposed by Kanger (which itself is a variant of Gentzen's system). The two variations in CK-LOG are, (i). the use of a new algorithm called the mating algorithm for testing proof terminations, and (ii) the use of specialized inference rules for reasoning about modal expressions using the possible world semantics.. The mating algorithm gives the theorem proving system of CK-LOG several new capabilities: to identify information that is pertinent to a given problem and retrieve it from its knowledge base, to update its models of possible worlds during the problem solving process based on the findings of the theorem proving system, to use these models of world states to test proof terminations, and to generate hypotheses during the problem solving process that are based on unknown information. These various features of CK-LOG are described here. The paper concludes with a discussion of the logic of frames as used in CK-LOG and establishes a condition called locality condition as a sufficient condition for creating knowledge representations with requisite completeness.Technical report DCS-TR-15
The Morse–Sard theorem for Clarke critical values
No full textArtículo de publicación ISIThe Morse–Sard theorem states that the set of critical values of a Ck smooth function defined on a
Euclidean space Rd has Lebesgue measure zero, provided k ≥ d. This result is hereby extended for
(generalized) critical values of continuous selections over a compactly indexed countable family of Ck
functions: it is shown that these functions are Lipschitz continuous and the set of their Clarke critical values
is null
Highly parallel and energy-efficient exhaustive minimum distance search engine using hybrid digital/analog circuit techniques
No full textA minimum distance search engine (MDSE) is presented as a hardware. accelerator for various exhaustive pattern-matching systems. This chip executes highly parallel computations of L-1-norms between an input query and stored multiple reference records, and searches for the minimum distance among them in a highly parallel fashion. Our architectural-level estimation shows that this MDSE can reduce energy dissipation by orders of magnitude as the number of records increases, compared with the conventional systems. We have designed a prototype 4-bit 8-word MDSE composed of merged memory logic (MML) and digital/analog-mixed winner-take-all circuit (DAM-WTAC) by using hybrid digital/analog circuit techniques. It was fabricated with a 0.6-mum single-poly triple-metal CMOS technology. Experimental results show that our chip works properly at 3 V/10 MM and has approximately four times larger throughput as well as four times higher energy efficiency, compared with the existing 8-bit microcontrollers.The author would like to thank MICROS, IDEC and Samsung Electronics
Company for their support. They would also like to thank the
reviewers for their valuable comments and Dr. K. Kim, Samsung Electronics
Company, for useful discussion
Variability study of Si nanowire FETs with different junction gradients
No full textRandom dopant fluctuation effects of gate-all-around Si nanowire field-effect transistors (FETs) are investigated in terms of different diameters and junction gradients. The nanowire FETs with smaller diameters or shorter junction gradients increase relative variations of the drain currents and the mismatch of the drain currents between source-drain and drain-source bias change in the saturation regime. Smaller diameters decreased current drivability critically compared to standard deviations of the drain currents, thus inducing greater relative variations of the drain currents. Shorter junction gradients form high potential barriers in the source-side lightly-doped extension regions at on-state, which determines the magnitude of the drain currents and fluctuates the drain currents greatly under thermionic-emission mechanism. On the other hand, longer junction gradients affect lateral field to fluctuate the drain currents greatly. These physical phenomena coincide with correlations of the variations between drain currents and electrical parameters such as threshold voltages and parasitic resistances. The nanowire FETs with relatively-larger diameters and longer junction gradients without degrading short channel characteristics are suggested to minimize the relative variations and the mismatch of the drain currents. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).1163Ysciescopu
Phenazine-1-carboxylic acid (PCA) produced by Paraburkholderia phenazinium CK-PC1 aids postgermination growth of Xyris complanata seedlings with germination induced by Penicillium rolfsii Y-1
No full textSymbiosis of Penicillium rolfsii Y-1 is essential for the seed germination of Hawaii yellow-eyed grass (Xyris complanata). However, the local soil where the plants grow naturally often suppresses the radicle growth of the seedlings. This radicle growth was drastically restored by coinoculation of Paraburkholderia phenazinium isolate CK-PC1, which is a rhizobacterium of X. complanata. It was found that the isolate CK-PC1 produced phenazine-1-carboxylic acid (PCA, 1) as a major metabolite. The biological effects of PCA (1) were investigated using the seeds of X. complanata and Mung bean (Vigna radiata) and it was uncovered that the symbiosis of the isolate CK-PC1was essential for the postgermination growth of X. complanata and the metabolite PCA (1) might partially contribute to promote the growth of the plants
Inside the Matrix: CTI Frameworks as Partial Abstractions of Complex Threats
No full textThe Cyber Threat Intelligence (CTI) field has evolved rapidly and most of its reporting is now fairly stan-dardized. Where the Cyber Kill Chain was its sole reference framework 5 years ago, today ATT&CK is the de facto standard for reporting adversary tactics, techniques and procedures (TTPs). CTI frameworks are effectively abstraction layers of malicious behavior and thus effective CTI dissemination hinges on their ability to accurately represent this behavior. We argue that this is an area with significant opportunity for improvement. The aforementioned models are attacker- and intrusion-centric, while much of the CTI reporting currently is artifact- and malware-centric. In other words, most analysis is performed using artifacts of adversary tools, while in-the-wild evidence of adversary techniques and procedures is limited or lacking. Applying an intrusion model to artifact-based analysis leads to information loss, affecting and potentially misleading CTI-based decision-making. Intelligence analysis naturally builds on imperfect information, but CTI frameworks should be oriented more towards this key premise. In this conceptual work we compare the intrusion-centric ATT&CK with Malware Behavior Catalog (MBC), which is malware-centric. We compare how their application affects reporting of analysis outcomes. For this we reverse a piece of APT malware, replicating how many CTI reports are produced. We find that compared to ATT&CK, the abstraction offered by MBC enhances the information density of our reporting. While currently in most industry malware reports ATT&CK is applied, our analysis shows that on these occasions using MBC, potentially in tandem with ATT&CK, improves reporting. With the daily amount of new malware samples only increasing, accurate behavior labeling is key to the success of CTI sharing and dissemination.Accepted author manuscriptCyber Securit
Are language production problems apparent in adults who no longer meet diagnostic criteria for attention-deficit/hyperactivity disorder?
No full textIn this study, we examined sentence production in a sample of adults (N = 21) who had had attention-deficit/hyperactivity disorder (ADHD) as children, but as adults no longer met DSM-IV diagnostic criteria (APA, 2000). This “remitted” group was assessed on a sentence production task. On each trial, participants saw two objects and a verb. Their task was to construct a sentence using the objects as arguments of the verb. Results showed more ungrammatical and disfluent utterances with one particular type of verb (i.e., participle). In a second set of analyses, we compared the remitted group to both control participants and a “persistent” group, who had ADHD as children and as adults. Results showed that remitters were more likely to produce ungrammatical utterances and to make repair disfluencies compared to controls, and they patterned more similarly to ADHD participants. Conclusions focus on language output in remitted ADHD, and the role of executive functions in language production
Observation of the Λ0b → Λ+cK+K-π- decay
No full textThe Lambda(0)(b) -> Lambda+cK+K-pi(-) decay is observed for the first time using a data sample of proton-proton collisions at centre-of-mass energies of root s = 7 and 8 TeV collected by the LHCb detector, corresponding to an integrated luminosity of 3fb(-1). The ratio of branching fractions between the Lambda(0)(b) -> Lambda K-+(c)+ K-pi(-) and the Lambda(0)(b) -> Lambda D-+(c)s(-) decays is measured to be B(Lambda(0)(b) -> Lambda+cK+K-pi(-))/B(Lambda(0)(b) -> Lambda D-+(c)s(-)) = (9.26 +/- 0.29 +/- 0.46 +/- 0.26) x 10(-2), where the first uncertainty is statistical, the second systematic and the third is due to the knowledge of the D-s(-) -> K+K-pi(-) branching fraction. No structure on the invariant mass distribution of the Lambda K-+(c)+ system is found, consistent with no open-charm pentaquark signature. (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Optimization of mitigation deployment using deep reinforcement learning over an enhanced ATT &CK
No full text\ua9 The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature 2024.This study introduces a Deep Reinforcement Learning approach (DRL-MD) aimed at optimizing the deployment of mitigations to minimize redundancy while ensuring effective defense against cyberattacks. DRL-MD initially enhances ATT &CK (Adversarial Tactics, Techniques, and Common Knowledge) to underscore the formal relationships between attacks and defenses. Over the enhanced ATT &CK, DRL-MD then operates in two phases: (1) Estimating Node Importance: DRL-MD proposes a model to estimate the importance of deployed nodes in the network, prioritizing mitigation deployment locations for better evaluation of mitigation effectiveness; and (2) Optimizing Mitigation Deployment: A Soft Actor-Critic algorithm finds the optimal mitigation deployment policy through multi-objective optimization of the importance of deployed nodes, the effectiveness of mitigations in preventing cyberattacks, vulnerability repair, and deployment cost. A case study with DRL-MD against the state-of-the-art counterparts has been performed considering the WannaCry threat, and results indicate that: (1) DRL-MD performs the best with 6.4–11% decrease in deployment cost; and (2) DRL-MD can significantly reduce redundancy in mitigation deployments, which partially benefits from the enhanced ATT &CK model. Overall, a comprehensive solution of mitigation deployment has been fostered to significantly lower the redundancy with more effective defenses against cyberattacks sustained
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Hong Kong: workfare in the world's freest economy
No full textWorkfare was introduced in many countries to suppress welfare dependency and reduce social security expenditures. However, workfare was launched in Hong Kong when there was only a relatively small social security budget and its citizens still strongly adhered to the ideologies of self-reliance. It was found that workfare has performed several functions in Hong Kong. Firstly, it has forced unemployed claimants to give up benefits so that Hong Kong's social security expenditures can be saved. Secondly, workfare had combined with Hong Kong's semi-democratic polity so that extremely stigmatising welfare measures were implemented. Thirdly, it has pushed poor citizens to the labour market without having any protection over wages and working hours. Thus, the combination of workfare and a semi-democratic polity has successfully suppressed Hong Kong's welfare demands and strengthened its self-help spirit. As a result, Hong Kong's minimal social security scheme and its low tax policy have been maintained
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