Dynamic sharing of a multiple access channel

In this paper we consider the mutual exclusion problem on a multiple access channel. Mutual exclusion is one of the fundamental problems in distributed computing. In the classic version of this problem, n processes perform a concurrent program which occasionally triggers some of them to use shared resources, such as memory, communication channel, device, etc. The goal is to design a distributed algorithm to control entries and exits to/from the shared resource in such a way that in any time there is at most one process accessing it. We consider both the classic and a slightly weaker version of mutual exclusion, called ep-mutual-exclusion, where for each period of a process staying in the critical section the probability that there is some other process in the critical section is at most ep. We show that there are channel settings, where the classic mutual exclusion is not feasible even for randomized algorithms, while ep-mutual-exclusion is. In more relaxed channel settings, we prove an exponential gap between the makespan complexity of the classic mutual exclusion problem and its weaker ep-exclusion version. We also show how to guarantee fairness of mutual exclusion algorithms, i.e., that each process that wants to enter the critical section will eventually succeed

Groźba bezprawna jako znamię przestępstwa z art. 245 k.k. : rozważania na tle orzecznictwa Sądu Najwyższego i sądów apelacyjnych

This article aims to interpret the term “unlawful threat” under Article 245 of the Criminal Code. It can be observed that judicial decisions of the Supreme Court and legal doctrine do not provide a uniform interpretation of the term. The work discusses whether the result in the shape of a justified concern that the threat will be carried out is necessary. Such a criminal result is described in Article 190 of the Criminal Code which penalizes punishable threats. It corresponds with Article 115 § 12 of the Criminal Code which defines an unlawful threat. In the opinion of the authors, causing a justified fear that the threat will be carried out is one of the statutory features in all three cases, i.e. unlawful threats to commit a criminal offence, to institute criminal proceedings and to disseminate defamatory information.Celem niniejszego artykułu jest dokonanie wykładni znamienia groźby bezprawnej występującego na gruncie art. 245 k.k. We wskazanym zakresie brak jest jednolitości w orzecznictwie Sądu Najwyższego, sądów apelacyjnych oraz w doktrynie. Zasadniczy problem wiąże się z kwestią zawierania się w pojęciu groźby bezprawnej skutku w postaci wzbudzenia uzasadnionej obawy spełnienia groźby. Skutek ten został określony w art. 190 k.k. opisującym przestępstwo tzw. groźby karalnej, do którego odsyła definicja ustawowa groźby bezprawnej określona w art. 115 § 12 k.k. W ocenie autorów skutek polegający na powstaniu uzasadnionej obawy spełnienia groźby należy do elementów groźby bezprawnej we wszystkich trzech przypadkach, tj. w przypadku groźby popełnienia przestępstwa, spowodowania postępowania karnego lub rozgłoszenia infamującej wiadomości

April 8, 1984

Abstract. Distributed Hash Tables (DHTs) enable fully distributed Peer-to-Peer network construction and maintenance with name-driven routing. There exist very few DHT approaches that consider heterogeneity of nodes inside the construction process or properly serve data of different load. To our best knowledge, there is no construction which smoothly addresses both these issues. We propose a Peer-to-Peer construction that explicitly uses heterogeneity to simplify the routing and maintenance process even in the presence of an adaptive adversary. Using a hypercube and cube connected cycles networks as a backbone, we show how to cope with two types of heterogeneity: one for nodes and one for data

Conceptions of inept attempt because of the subject in judicial practice (on the margin of the Supreme Court’s resolution I KZP 16/16)

The article deals with the issue of inept attempt because of the subject in judicial practice in reference to the Supreme Court’s resolution I KZP 16/16. Two antagonistic approaches were presented: objective approach and subjective approach, as well as mixed approaches. Artkuł dotyczy usiłowania nieudolnego ze względu na przedmiot w praktyce sądowej w odniesieniu do uchwały Sądu Najwyższego I KZP 16/16. Omówiono tu dwa antagonistyczne względem siebie stanowiska: koncepcję obiektywistyczną (obiektywną) oraz koncepcję subiektywistyczną (subiektywną), a także koncepcje mieszane.

Distributed Alarming in the On-Duty and Off-Duty Models

Decentralized monitoring and alarming systems can be an attractive alternative to centralized architectures. Distributed sensor nodes (e.g., in the smart grid's distribution network) are closer to an observed event than a global and remote observer or controller. This improves the visibility and response time of the system. Moreover, in a distributed system, local problems may also be handled locally and without overloading the communication network. This paper studies alarming from a distributed computing perspective and for two fundamentally different scenarios: on-duty and off-duty. We model the alarming system as a sensor network consisting of a set of distributed nodes performing local measurements to sense events. In order to avoid false alarms, the sensor nodes cooperate and only escalate an event (i.e., raise an alarm) if the number of sensor nodes sensing an event exceeds a certain threshold. In the on-duty scenario, nodes not affected by the event can actively help in the communication process, while in the off-duty scenario, non-event nodes are inactive. We present and analyze algorithms that minimize the reaction time of the monitoring system while avoiding unnecessary message transmissions. We investigate time and message complexity tradeoffs in different settings, and also shed light on the optimality of our algorithms by deriving cost lower bounds for distributed alarming systems.13 page(s