Buffers Management

Buffers are often used in Construction to prevent the negative impact of Variability and Uncertainty on projects. Inventories of materials, budget contingencies, time float, and excess of equipment capacity are examples of the type of Buffers found in construction. However, usually the design and management of Buffers is based mostly on intuition and performed informally. New production philosophies such as Lean Production, Lean Construction and Theory of Constraints allow a more systematic and rigorous approach to the Design and Management of Buffers. This paper discusses the role of production management philosophies in the Design and Management of Buffers, and how selected IT tools can support this process.  The paper also provides some guidelines for the design of Buffers in repetitive construction projects using a proposed conceptual model.

This paper proposes an improved critical chain method with fuzzy approach to schedule projects under uncertainty. Utilizing fuzzy numbers can be wise because of the natural uncertainty in estimation of required work to accomplish the project tasks. To minimize the project duration as an objective taking into account resource limitations and other constrains, a Resource Constraint Project Scheduling Problem model (RCPSP) is adopted. The outputs of this model determine the project schedule. Then, regarding to CCPM concepts, a new buffer sizing method is introduced. As a result, a project buffer is added to the end of the project schedule and will be used if necessary. The methodology can be used as a control procedure.

Modern High-Performance Computing (HPC) systems are adding extra layers to the memory and storage hierarchy, named deep memory and storage hierarchy (DMSH), to increase I/O performance. New hardware technologies, such as NVMe and SSD, have been introduced in burst buuer installations to reduce the pressure for external storage and boost the burstiness of modern I/O systems. e DMSH has demonstrated its strength and potential in practice. However, each layer of DMSH is an independent heterogeneous system and data movement among more layers is signiicantly more complex even without considering heterogeneity. How to eeciently utilize the DMSH is a subject of research facing the HPC community. In this paper, we present the design and implementation of Hermes: a new, heterogeneous-aware, multi-tiered, dynamic, and distributed I/O buuering system. Hermes enables, manages, supervises , and, in some sense, extends I/O buuering to fully integrate into the DMSH. We introduce three novel data placement policies to eeciently utilize all layers and we present three novel techniques to perform memory, metadata, and communication management in hierarchical buuering systems. Our evaluation shows that, in addition to automatic data movement through the hierarchy, Hermes can signiicantly accelerate I/O and outperforms by more than 2x state-of-the-art buuering platforms.

This paper introduces a new approach to database disk buffering,
called the LFU-K method. The LFU-K page replacement algorithm is an improvement
to the Least Frequently Used (LFU) algorithm. The paper proposes
a theoretical-probability model for formal description of LFU-K algorithm. Using
this model we evaluate estimations for the LFU-K parameters. This paper
also describes an implementation of LFU-2 policy. As we demonstrate by
trace-driven simulation experiments, the LFU-2 algorithm provides significant
improvement over conventional buffering algorithms for the shared-nothing database
systems.

HSDPA specifications include support for a flexible framework for QoS management. In this paper, it is shown how buffer management could be incorporated into HSDPA QoS framework for 'multimedia' traffic QoS control in the MAC-hs of the Node-B. A time-space-priority (TSP) scheme is proposed as viable buffer management scheme to this effect. Comparative simulation study with other schemes is presented, demonstrating the effectiveness of the TSP buffer management scheme for 'multimedia' service QoS control in HSDPA Node-B data buffers.

Modern High-Performance Computing (HPC) systems are adding extra layers to the memory and storage hierarchy, named deep memory and storage hierarchy (DMSH), to increase I/O performance. New hardware technologies, such as NVMe and SSD, have been introduced in burst buuer installations to reduce the pressure for external storage and boost the burstiness of modern I/O systems. e DMSH has demonstrated its strength and potential in practice. However, each layer of DMSH is an independent heterogeneous system and data movement among more layers is signiicantly more complex even without considering heterogeneity. How to eeciently utilize the DMSH is a subject of research facing the HPC community. In this paper, we present the design and implementation of Hermes: a new, heterogeneous-aware, multi-tiered, dynamic, and distributed I/O buuering system. Hermes enables, manages, supervises , and, in some sense, extends I/O buuering to fully integrate into the DMSH. We introduce three novel data p...

One of the challenges in Delay Tolerant Wireless Sensor Networks (DT-WSN), is to handle situations where the available buffer space is insufficient-the buffer management problem. Although several buffer management algorithms have been proposed for DT-WSNs, to the best of our knowledge, there is no comprehensive study on the effects different factors have on their performance, and which evaluates the relative performance of these algorithms in different contexts. This paper evaluates in a fixed-factor factorial experiment the performance in terms of latency and Quality of Information (QoI) of four representative buffer management algorithms for DT-WSNs; two traditional, FiFO and Random, and two QoI-based algorithms-one proposed by Humber and Ngai and the SmartGap algorithm. The evaluation suggests that the buffer management algorithm in combination with employed routing protocol and the sensor node buffer sizes have a significant impact on latency, while the obtained QoI rather depen...

One of the challenges in Delay Tolerant Wireless Sensor Networks (DT-WSN), is to handle situations where the available buffer space is insufficient-the buffer management problem. Although several buffer management algorithms have been proposed for DT-WSNs, to the best of our knowledge, there is no comprehensive study on the effects different factors have on their performance, and which evaluates the relative performance of these algorithms in different contexts. This paper evaluates in a fixed-factor factorial experiment the performance in terms of latency and Quality of Information (QoI) of four representative buffer management algorithms for DT-WSNs; two traditional, FiFO and Random, and two QoI-based algorithms-one proposed by Humber and Ngai and the SmartGap algorithm. The evaluation suggests that the buffer management algorithm in combination with employed routing protocol and the sensor node buffer sizes have a significant impact on latency, while the obtained QoI rather depends on the characteristics of the transported data and the routing protocol, provided a single-copy routing protocol is used. Moreover, the evaluation suggests that QoI-based buffer management algorithms do offer improved QoI, with an 31% improvement in MAE for SmartGap compared to FIFO. However, they do so at the expense of higher latency, with SmartGap giving a 60% higher latency than FIFO on average.

One of the effective factors for the progress of developing countries is population growth rate which creates the progress field and ensures development in the areas such as social, economic, political, cultural, and military. This paper predicts the population growth rate of Iran (2005-2015) by multiple linear regression method based on the factors such as GDP, Unemployment Rate, Inflation Rate, Construction Growth Rate of Residential Building, and Population Rate. Then using the logarithmic transformation method, leads to .18% reduction in deviation and 35.3% increase in correlation coefficient. Finally the influence of the factors on population growth rate is investigated which is used for population policy decisions of developing countries.