An M/M/1 queueing system with second optional service and unreliable server is studied. We consider that the server works at different rate rather than being idle during the vacation period. The customers arrive to the system according to Poisson process with state dependent rates depending upon the server’s status. All customers demand the first essential service whereas only some of them dema...

Even though the (untwisted) Whitehead doubling operation kills all known abelian invariants of knots (and makes them topologically slice), we show that it does not kill the rational function that equals to the 2-loop part of the Kontsevich integral.

The present study examined adult age differences in processing emotional faces using a psychological refractory period paradigm. We used both behavioral and event-related potential (P1 component) measures. Task 1 was tone discrimination (fuzzy vs. pure tones) and Task 2 was emotional facial discrimination ("happy" vs. "angry" faces). The stimulus onset asynchrony (SOA) between the two tasks was...

In many situations people need to mentally adopt the (spatial) perspective of other persons, an ability that is referred to as "Level 2 perspective taking." Its underlying processes have been ascribed to mental self-rotation that can be dissociated from mental object-rotation. Recent findings suggest that perspective taking/self-rotation may not require central capacity. By using the psychologi...

The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasin...

Four reaction time experiments examined the mental rotation process using a psychological refractory period paradigm. On each trial, participants made speeded responses to both a tone (S1) and a rotated letter (S2), presented with varying stimulus onset asynchronies (SOAs). If mental rotation of the stimulus letter can proceed while central mechanisms are busy with S1, then the effect of orient...

We present a new methodology to derive faster composite operations of the form dP + Q, where d is a small integer ≥ 2, for generic ECC scalar multiplications over prime fields. In particular, we present an efficient Doubling-Addition (DA) operation that can be exploited to accelerate most scalar multiplication methods, including multiscalar variants. We also present a new precomputation scheme ...

this paper studies an m/g/1 repairable queueing system with multiple vacations and n-policy, in which the service station is subject to occasional random breakdowns. when the service station breaks down, it is repaired by a repair facility. moreover, the repair facility may fail during the repair period of the service station. the failed repair facility resumes repair after completion of its re...

Controversy has plagued the question of whether verbal “object markers” (OMs) are object pronouns cliticized to the verb or realizations of object agreement. Beginning with data from Amharic, we develop a reliable and consistent diagnostic for resolving this question. Specifically, we claim that OMs should be analyzed as clitic pronouns if and only if they are unable to double nominals that are...

In a parity judgment task, the ERPs at parietal electrode sites become more negative as more mental rotation has to be executed. This article provides a review of the empirical evidence regarding this amplitude modulation. More specifically, experiments are reported that validate both the functional relationship between mental rotation and the amplitude modulation as well as the temporal relati...