International Business Machines Corporation

Parviz Kermani

Mahmoud Naghshineh

Babak Rezvani

Claus Michael Olsen

Manish Satyapal Gupta

Manoj Kumar Agarwal

Anindya Neogi

Gautam Kar

Peter Dirk Hortensius

Danny N McKay

Hani Talal Jamjoom

Raymond Byars Jennings, Iii

Debanjan Saha

Fritz R Gfeller

Frank P Novak

Patrick K Kam

Werner K Bux

Wolfgang B Kleinoeder

Timucin Ozugur

Described are methods, apparatus and computer programs for determining run-time dependencies between logical components of a data processing environment. Components of the data processing environment are monitored by monitoring agents accessing run-time activity data via APIs of the managed system. A dependency generator identifies correlations between the run-time activity of the monitored components. For synchronous monitored systems, the dependency generator calculates an activity period for monitored components and determines which component's activity periods contain the activity periods of other components. Containment is used as an indicator of a likely dependency relationship, and a weighting is computed for each dependency relationship based on the consistency of containment.

Systems, methods and computer programs for determining dependencies between logical components in a data processing system or network

An exemplary method for identifying process elements includes the steps of obtaining a plurality of relevant request-response pairs including request identifiers, mapping the request identifiers to corresponding artifacts, identifying actions based on the artifacts, and mapping the actions to process elements such that each given one of the process elements has an associated artifact.

Apparatus and method for identifying process elements using request-response pairs, a process graph and noise reduction in the graph

Rate management in adaptive data rate wireless communication systems in which communicating stations move with respect to one another implements algorithms for calculation of the repetition rate. A rate management module is used for selecting a proper value of repetition rate to be communicated back to sending station and for a selecting proper value of repetition rate to encode the data at the sending station. The repetition rate calculation procedure enables each station to dynamically calculate the optimum rate with which each station should be receiving information from another station. The repetition rate calculation procedures take into consideration past and present measurements of the link quality, age of the link quality measurements, speed of change in the link quality, packet types, packet lengths, received signal strength, and pattern and correlation in the link quality measurements. The rate management module utilizes one or more tables which are accessible from either hardware or software.

Rate selection in adaptive data rate systems

Fairness algorithms and access methods enable non-zero channel access for wireless communication systems operating in a random access channel environment. Fair access to a random access channel for each station in a wireless network is assured by each station calculating a priority or probability for accessing the channel based on logical connections among certain stations, based on other stations perception of the channel and based on each calculating station's own perception of the channel properties.

Balanced media access methods for wireless networks

The throughput of a Request-to-Send and Clear-to-Send (RTS/CTS) based distributed media access control protocol is improved by reserving the medium in a hierarchical fashion. The shared medium is reserved for two stations called the participants. During the reserved period, a master (or primary) attribute and a slave (or secondary) attribute are given to the participants and the medium is shared between them using any suitable coordination algorithm. During the reserved time, the secondary can signal the primary station that it has data to send to the primary station and request that the primary and secondary roles or attributes be exchanged. In the case that a role exchange takes place, control of the medium is transferred from one station to another and data transfer in an opposite direction can take place without requiring another reservation. Observing stations which are not participating in the reservation can be invited to join the reservation as additional secondary stations if this does not cause any interference to any other existing reservations. The efficiency of the medium reservation may be improved also by piggy-backing any reservation specific signals onto data packets and by defining new response frames such as Hold-to-Send (HTS) and Free-to-Send (FTS) for flow control when there is a congested receiving station.

Extensions to distributed MAC protocols with collision avoidance using

In a wireless multi-rate communications system, a method for extending the range of communications in the system by dividing the physical layer frame into two portions: a robust header portion and a body, where the repetition rate of the data symbols in the header portion is greater than or equal to the repetition rate of the data symbols in the body of the frame. In this way the header can be received and decoded by all stations in the system with a high probability, while the body of the frame need only be received and decoded by the destination station to which the body of the frame is intended to be received and decoded.

Media access control protocols in a wireless communication network

A method of delievering data in a wireless communications network using a combination of collision sensing and collision avoiidance protocols. More precisely, if there are no hidden nodes detected in the network, a collision sensing protocol is used; however, if there are hidden nodes, then a collision avoidance protocol is used. This invention also deals with methods of determining the presence or absence of hidden nodes.

Schemes to determine presence of hidden terminals in wireless networks

In the Checkpoint Mode Protocol (CPM), checkpoint frames are transmitted at regular intervals for acknowledging received information frames and individually requesting retransmission of missing information frames. The disclosed invention reduces the flow of checkpoint frames in situations where their information is not required. This is achieved by either sending a Stop Checkpointing frame from sender to receiver in particular situations, or by inserting, in the case of duplex transmission (i.e. both stations are sending and receiving), Request-Reply bits into normal checkpoint frames for suppressing the flow of checkpoint frames when they are not necessary. In each case, provisions are made to resume the transmission of checkpoint frames as soon as they are required again.

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South Salem, NY, United States of America

Parviz Kermani