Free Token Research Articles

The servicing system MAP(PH)+MAP/PH/N/R as a model of optimizing an HTTP server with blockings

We consider a multiline queueing system with joint or single queries. The number of queries in a connection is random and is not known when the connection is established. Queries arriving during each connection are described by the phase type input steam. Accepting a connection in the system is restricted by tokens. Connections arriving when no free tokens are present are refused. Single queries arrive without tokens. If the number of free slots in the system is not enough, the system is blocked.

Queueing system with a phase process of query arrival in session

A multi-server quenching system with sessional query arrival is considered. The query arrival in each session is described by the considerably Phase Type (PH) arrival flow. The session acceptance in the system is limited with the help of tokens. Sessions that come into the system at the moment when free tokens are lacking are rejected. An algorithm for finding the joint distribution of the number of sessions and the number of queries in the system is provided. Several problems of the system’s parameters optimization are considered.

Financial Aspects of the Social Security “Problem”

There is a widespread belief that the Social Security Trust Fund is going bankrupt. Thus, while Old-Age and Survivors Insurance and Disability Insurance (OASDI) is currently accumulating large financial surpluses, the fear is that Social Security faces a financial crisis because post-2020 program expenditures are expected to exceed revenues.1 The solution, many argue, is to use (current and future) budget surpluses to save Social Security from financial collapse.2 The idea, according to these saviors, is that by depositing the surpluses into a trust fund, the Treasury can be prevented from spending them. Many of these saviors also insist that the rest of the government's budget must remain balanced, for otherwise the Treasury would be forced to dip into Social Security reserves. We examine these points by first providing an analogy. Can a trust fund help to provide for future retirees? Suppose the New York Transit Authority (NYTA) offered subway tokens as part of the retirement package provided to employees--say, 50 free tokens per month (for life) upon retirement. Does this mean that New York should attempt to run an annual surplus of tokens (on average collecting more tokens per month than are paid out) in order to accumulate a trust fund to provide for future NYTA retirees? Of course not. When tokens are needed to pay future retirees, New York will simply issue more tokens at that time. Not only is it unnecessary for New York to accumulate a hoard of tokens, but it will not in any way ease the burden of providing subway rides to future retirees.

A new token ring protocol and its performance for single and dual ring lan systems

AbstractThis paper presents a new protocol for token ring local computer networks and its performance for single and dual ring networks using simulation modelling. The proposed protocol is a modification of the IEEE 802·5 token ring standard. In this protocol, a station can start transmission if it receives a free token or a data packet passing its interface logic. Idle stations are skipped whenever there is at least one station that has a ready packet to transmit. This is achieved by using two of the reserved bits in the frame status (FS) field. The bits used are called transmission reservation bits (TR‐bits). The TR‐bits are reset by the sending station and set by the first station that has data to transmit during the round trip of the associated packet along the ring. It is found that the proposed modified token ring (MTR) protocol provides better throughput and delay performance for both the single and dual ring networks. The reduction in mean delay of the MTR as compared to the standard token ring (STR) reaches about 45 per cent under heavy traffic conditions. Moreover, it is found that the performance of the MTR decreases as the packet size increases but remains higher than the corresponding performance of the STR for both the single and dual ring networks. The MTR provides a maximum throughput improvement of about 6 per cent over the STR for both dual and single ring cases. Finally, the proposed protocol (MTR) is easy to implement, with no extra hardware and has low cost/performance characteristics.

Distributed protocol for integrated voice/data token passing ring networks

In this paper we present a distributed protocol for integrated voice/data token passing ring networks. No central control station is needed, and hence the fault tolerance of the network is expected to be increased. Bandwidth is dynamically allocated according to the varying traffic load. A dynamic counter, appended to the free token, is used to control the number of voice call connections on the ring. The data traffic flow is controlled by using two local counters kept at each network station. To improve the throughput of the network, silent voice slots are allowed to carry data packets. We have shown that the real-time constraints of the voice traffic are well satisfied under this protocol. A set of guidelines are derived to determine the maximum number of voice calls allowed on the ring according to the current network environments. Criteria for determining the packet length and the buffer size of voice packets are also provided. Numerical results show that our protocol exhibits a well-controlled packet delay for data traffic and the maximum delay of each voice packet is about B times the generation time of a voice packet, where B is the number of pre-allocated voice packet buffers per voice call.

Analytic models of cyclic service systems and their application to token-passing local networks

Using the framework of cyclic-service systems with a single server, two different token-passing models are investigated. The first model is approximate, obtaining the free-tokens cycle-time distribution on an asymmetric system with infinite capacity buffers and single-token operation. The second model is exact, yielding the cycle-time distribution of the free token on an asymmetric system with unit-capacity buffers, and single-token operation. The latter result is verified using known results for symmetric, unit-capacity buffer systems. To demonstrate the positive effects of buffering, a small variation of the unit-capacity buffering scheme is introduced. Computational results include performance measures such as throughput, utilization, loss probabilities, mean cycle times, cycle-time distributions, and a comparison of two buffering schemes.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effects of a Student-Managed Response-Cost System on the Behavior of Two Mainstreamed Students

This study illustrates the use of a student-managed response-cost system using free tokens to modify the on-task behavior of 2 mainstreamed students-an emotionally disturbed fourth grader and a learning disabled sixth grader-in regular classrooms. After the program was implemented, the subjects' on-task behavior as well as their academic performance improved. Applications of the findings to regular classrooms are discussed.

Effectiveness of a Group-Managed Interdependent Contingency System

An interdependent group-managed response-cost system mediated by free tokens was employed to decrease the inappropriate verbalizations of two groups of students labeled learning disabled. Results showed that this contingency system was a viable and effective method of decreasing inappropriate behavior. Reasons for the effectiveness of the treatment procedure are discussed.

Comparative effects of externally managed and self-managed response-cost systems on inappropriate classroom behavior

This study compares the relative efficacy of externally managed and self- managed free token response-cost systems in decreasing the inappropriate behavior of two learning-disabled students. The differential effects of the two treatment conditions were assessed by using an alternating treatments design. Experimental control was demonstrated by adding reversal phases comparing the treatments with baseline conditions. The results indicated that the two treatment conditions are equally effective in decreasing inappropriate behavior. The reasons for and implications of the findings are discussed.

The differential effect of two free ride dissemination procedures on bus ridership

In an attempt to isolate the operating variables that increase transit ridership under conditions of free transit, the following experimental conditions were instituted on a university campus bus system: (1) dissemination of free transit tokens regardless of the subject's bus riding behavior (non-contingent free transit), (2) dissemination of one free token for each bus ride made by the subject (one-for-one contingent free transit), and (3) dissemination of three free transit tokens for each bus ride made by the subject (three-for-one contingent free transit). It was found that the requirement of a response contingency (i.e. a subject must ride to get additional free transit) produced greater transit usage than the dissemination of free transit regardless of the subject's bus riding behavior. Of the two response contingent conditions, the one-for-one contingent free transit condition produced ridership levels greater than the three-for-one contingent free transit condition. Additionally, trading of free transit tokens was highest under the non-contingent free transit condition.