Feeding Buffer Research Articles

Implementation of the Critical Chain Project Management (CCPM) Model for Improving Time and Cost in a Project for House Type 36

Purpose: This study was conducted on a housing project in Type 36 Housing using the Critical Chain Project Management (CCPM) approach. The objective of this research was to achieve a more effective project timeline and a more efficient total project cost. Research methodology: By eliminating 50% of the safety time, the method minimizes the safe time to achieve a 50% probability of completion without additional safety time using Critical Chain Project Management or CCPM in this project. Results: This approach results in a reduction of the project completion time from the original 18 working days to 15 working days. Additionally, this implementation leads to cost savings, with the calculated daily cost amounting to Rp.10,907,170.03. Through the application of Critical Chain Project Management, a 4-day Feeding Buffer and an 11-day Project Buffer were established. As a result, the completion time for the Type 36 house construction is reduced to 15 days, which is 3 days shorter than the initial project schedule of 18. Limitations: This analyzing just focus on critical process but not for opportunity job can be reduce for more improvement. And this research only focus in Construction Project. Contribution: This research can be use for practical in the project that have critical job need to prepare and control to achive project target, with cost reduction for Rp.10,907,170.03 and project time reduction for 3 days

An MINLP Model for Project Scheduling with Feeding Buffer

An MINLP Model for Project Scheduling with Feeding Buffer

An MINLP model for project scheduling with feeding buffer

An MINLP model for project scheduling with feeding buffer

Productivity Analysis Using the Critical Chain Project Method Management (CCPM) on Repair Projects Geomarin-III ship 649 DWT.

Ship repair project planning still often encountered problems that delay ship repair projects to achieve complete ship repair projects. Delays are due to frequent mismatches between ship repair scheduling and conditions that occur at the shipyard. The most commonly used method is the Critical Path Method (CPM). But in reality, the CPM method is considered less effective because there is still safety time for each job. Technological developments found the latest method, namely Critical Chain Project Management (CCPM). This method removes the safety time contained in the CPM method and replaces it with buffer time which is placed at the end of work activities. This study aims to analyze the duration of the critical path, determine labor costs, and the amount of buffer duration on the repair of the Geomarin-III 649 DWT ship. Based on the calculation results obtained on the repair of the Geomarin-III 649 DWT ship with the Critical Chain Project Management (CCPM) method is 10 days, 10 days faster than the normal duration. The labor cost obtained using the CCPM method is IDR. 54,017,500, saving 35% of the normal cost is IDR. 82,680,000, but if the buffer time is used thoroughly, the total estimated labor cost for the CCPM method will increase due to the addition of labor and the duration of the buffer time obtained by the CCPM method as a substitute for safety time, which is 9 days project buffer and 3 days feeding buffers. Based on this research, it was found that the CCPM method is considered effective and can accelerate the duration of the project and minimize labor costs.

Critical chain based Proactive-Reactive scheduling for Resource-Constrained project scheduling under uncertainty

Project scheduling problems under both resource constraints and uncertainty have been widely studied due to their real world relevance. In this paper, we design and implement a new integrated proactive–reactive solution approach based on the critical chain method (CCM) to proactively generate a robust and reliable baseline schedule for the class of resource-constrained project scheduling problem (RCPSP) under uncertainty. A discrete-time Markov decision process model is applied for the reactive scheduling phase, which embeds the look-up table method in reinforcement learning to dynamically schedule and adjust schedule reactively using the baseline schedule during project execution. The cost values in the look-up table are calculated based on the occupation of a project buffer and feeding buffers in the baseline schedule generated by the CCM. We conduct computation experiments on the benchmark instances to test our algorithm. The results show that our approach is able to obtain quality solutions efficiently, and competitive with the benchmark algorithms for small- and medium-sized instances.

Buffer Sizing in Critical Chain Project Management by Brittle Risk Entropy

In order to solve the problems such as project duration delay caused by unreasonable buffer zone setting, a critical chain buffer zone setting method is proposed based on fragility theory. Firstly, we propose that the construction process is brittle and the brittleness of the construction process was analyzed. Secondly, this paper introduces a risk-integrated impact rate to describe the uncertainty of the construction process and establishes a brittle risk entropy function. Then, it presents entropy models and modification models of project buffers and feeding buffers based on the original Root Square Error Method. Finally, an engineering project was selected as an example, and the simulation was carried out using the Monte Carlo simulation software Crystal Ball, and the resulting method was compared with three buffer zone calculation methods. The results show that the method can effectively reduce the construction period and is effective and practical when compared to the other three buffer calculation methods. The results of the study provide a new way of thinking about buffer settings based on existing critical chain project management methods.

Perencanaan Proyek Struktur Semi Gantry Crane Menggunakan Critical Chain Project Management

Project completion work has problems related to project completion not being on time, thereby increasing costs and resources. The work on the gantry crane structure includes projects that experience problems related to incompatibility between project planning and actual project work. This study aims to plan project activities by speeding up processing time and providing prevention strategies to minimize project delays. This study uses the critical chain project management method using the cut & paste method by 30%. The results showed the total buffer time was ten days, consisting of eight project buffer days and two feeding buffer days. The total time for the semi-gantry crane structure project has accelerated from 43 days to 33 days. Suggestions for prevention that can be done to complete the project according to the plan are adding project workers, adding tools or machines, and eliminating multitasking activities that cause project workers not to finish their work immediately.

Traditional protocols and optimization methods lead to absent expression in a mycoplasma cell-free gene expression platform.

Cell-free expression (CFE) systems are one of the main platforms for building synthetic cells. A major drawback is the orthogonality of cell-free systems across species. To generate a CFE system compatible with recently established minimal cell constructs, we attempted to optimize a Mycoplasma bacterium-based CFE system using lysates of the genome-minimized cell JCVI-syn3A (Syn3A) and its close phylogenetic relative Mycoplasma capricolum (Mcap). To produce mycoplasma-derived crude lysates, we systematically tested methods commonly used for bacteria, based on the S30 protocol of Escherichia coli. Unexpectedly, after numerous attempts to optimize lysate production methods or composition of feeding buffer, none of the Mcap or Syn3A lysates supported cell-free gene expression. Only modest levels of in vitro transcription of RNA aptamers were observed. While our experimental systems were intended to perform transcription and translation, our assays focused on RNA. Further investigations identified persistently high ribonuclease (RNase) activity in all lysates, despite removal of recognizable nucleases from the respective genomes and attempts to inhibit nuclease activities in assorted CFE preparations. An alternative method using digitonin to permeabilize the mycoplasma cell membrane produced a lysate with diminished RNase activity yet still was unable to support cell-free gene expression. We found that intact mycoplasma cells poisoned E. coli cell-free extracts by degrading ribosomal RNAs, indicating that the mycoplasma cells, even the minimal cell, have a surface-associated RNase activity. However, it is not clear which gene encodes the RNase. This work summarizes attempts to produce mycoplasma-based CFE and serves as a cautionary tale for researchers entering this field. Graphical

A Platform Approach to Protein Encapsulates with Controllable Surface Chemistry.

The encapsulation of proteins into core-shell structures is a widely utilised strategy for controlling protein stability, delivery and release. Despite the recognised utility of these microstructures, however, core-shell fabrication routes are often too costly or poorly scalable to allow for industrial translation. Furthermore, many scalable routes rely upon emulsion-techniques implicating denaturing or environmentally harmful organic solvents. Herein, we investigate core-shell protein encapsulation through single-feed, aqueous spray drying: a cheap, industrially ubiquitous particle-formation technology in the absence of organic solvents. We show that an excipient’s preference for the surface of the spray dried particle is well-predicted by its hydrodynamic diameter (D) under relevant feed buffer conditions (pH and ionic strength) and that the predictive power of D is improved when measured at the spray dryer outlet temperature compared to room temperature ( = 0.64 vs. 0.59). Lastly, we leverage these findings to propose an adaptable design framework for fabricating core-shell protein encapsulates by single-feed aqueous spray drying.

A Project-Scheduling and Resource Management Heuristic Algorithm in the Construction of Combined Cycle Power Plant Projects

Given the growing number of development projects, proper project planning and management are crucial. The purpose of this paper is to introduce a heuristic algorithm for scheduling a power plant project construction and project resource management to determine the size of project buffers and feeding buffers. This algorithm consists of three steps: 1. estimating the duration of project activities; 2. determining the size of the project buffer and feeding buffers; and 3. simulating the mentioned algorithm, which will be explained below. Innovations of this research are as follows: estimating the exact duration of project activities by using a heuristic algorithm, in addition to determining the buffer size; calculating both project buffer and feeding buffers; and applying the algorithm to implement an ACC used in combined cycle power plant projects as a numerical example. In order to evaluate the proposed algorithm, inputs from this project were run through several algorithms recently presented. The results showed that a suitable amount of buffers can be allocated for projects using this algorithm.

A heuristic algorithm in project scheduling and project time optimization: through managing the size of the project buffer, feeding buffers, and resource buffers

Execution of projects is not always done according to the original plan, and in many cases, projects are accompanied by delays, which will lead to financial and time losses for companies and organizations. This research is introduced an innovative heuristic algorithm for more accurate scheduling of projects and minimizing delays in them by managing project buffers and determining their size. Providing a heuristic algorithm to determine the size of project buffer, feeding buffers, and resource buffers simultaneously is the innovation of this research. The proposed heuristic algorithm is coded and run in MATLAB software to analyze the data and also evaluate its performance and the results are compared with similar previous algorithms. The results are showed that using this algorithm will have better results than similar algorithms and will increase project productivity and projects can be completed in a shorter time.

Planning & Controlling Tourism Landscape Design Project using Critical Chain Project Management (CCPM) Schedulling

Project Management must meet the performance criteria of timeliness and budget control agreed between the project owner, contractor and supervisor. However, the level of uncertainty in the project implementation process is very high and causes delays and over budgeting. The Village Nongkojajar is a Proposed Integrated Agropark Project as a result of the revitalization of the non-productive land of the Horticultural Seed Farm owned by the Government of East Java Province. The Landscape Architecture Project has a Creative Value Chain which is divided into Creation - Implementation - Management. Therefore scheduling and controlling the project becomes important in order to to estimate working time and the project remains in accordance with the predetermined project timeline and whenever corrective action is needed. The relevance of Project Management in this research is that with high project problems, require a good planning process. The Project can be completed quickly than the specified time and more cost effective. Critical Chain Project Management (CCPM) is one method for completing and preparing projects that focus on the resource requirements for implementing projects by adding project buffers, feeding buffers and resource buffers. By analyzing using CCPM, researchers can look for optimization and control in implementing project scheduling.

356 Anomalies of Carbohydrate Digestion and Metabolism by Ruminants

Abstract Carbohydrate, derived either from plant cell walls (neutral detergent fiber; NDF) from fresh or conserved forages consumed by cows and growing cattle or from starch of grains and concentrates in commercial feedlot diets, provides most of the dietary energy for ruminant growth and production. The ruminants’ ability to harvest forage from remote, inaccessible locations, to scavenge energy from NDF of feeds and byproducts of grain largely indigestible by non-ruminants, and to employ non-protein N to form protein-rich, nutrient-dense foods for humans are key ecological advantages over non-ruminants. Outlined below are some topics needing research attention. First, feed composition tables invariably indicate that the digested energy (DE) of carbohydrates is 4.4 kilocalories per gram, yet the gross energy (GE) of purified carbohydrate polymers (starch; cellulose, glycogen) averages 4.18; monomers (hexoses, pentoses) average 3.74. Having DE exceed GE violates the first Law of Thermodynamics! Might this 5 percent discrepancy reflect underestimations of fecal lignin or of protein digestibility due to metabolic fecal N? Favoring feeds rich in carbohydrate, this discrepancy confounds formulation of least-cost diets. Secondly, site of digestion of carbohydrate alters its metabolizable energy (ME). Fermentation, though required to yield ME from NDF, generates methane and heat. In contrast, starches and sugars that escape ruminal fermentation, if digested in the small intestine, circumvent these losses increasing their relative ME. Unfortunately, when ruminally fermented, starch, either directly or via pH depression, reduces NDF fermentation; might ruminal NDF digestion be increased by feeding NDF plus buffer versus concentrate diet components asynchronously? Third, carbohydrate metabolites lost in urine (lactate, pentoses, hippuric acid) need further quantification. Finally, ruminally-formed metabolites (methylglyoxal, methane) adversely affect animal health and energetics. Ruminal modification (site- or time-targeted enzymes or inhibitors; altering the ruminal microbiome with pre- or probiotics, inoculants, nutraceuticals) should help enhance ruminant productivity and sustainability.

Cash Flow Optimization for Renewable Energy Construction Projects with a New Approach to Critical Chain Scheduling

This study concerns the use of the critical chain method to schedule the construction of renewable energy facilities. The critical chain method is recognized as a useful project management tool, transforming a stochastic problem of uncertainty in activity durations into a deterministic one. However, this method has some shortcomings. There are no clear principles of grouping non-critical activities into feeding chains. Another ambiguity is sizing the feeding buffers with regard to the topology of the network model and the resulting dependencies between activities, located in different chains. As a result, it is often necessary to arbitrarily adjust the calculated sizes of feeding buffers before inserting them into the schedule. The authors present the new approach to sizing the time buffers in the schedule, enabling a quick assessment of the quality of a given solution variant and finding a solution that best meets the established criteria, conditions, and constraints. The essence of the presented approach is the two-step sizing of time buffers with the use of deterministic optimization and stochastic optimization techniques. Taking into account construction management needs, the optimization criteria are based on the construction project cash flow analysis. The effectiveness of the presented approach is illustrated by an example of developing a wind power plant construction schedule. According to the results, the presented approach ensures the protection of the scheduled completion date of the construction and the stability of the schedule.

Analysis of Time Efficiency with CCPM Method and BIM in Construction Projects Construction of High-Rise Residential Building Basement

Development in Indonesia is experiencing a rapid increase, a lot of vacant land is used by investors to construct buildings. The implementation of the construction must pay attention to the project schedule, work delays often occur. The factors that cause work delays are usually from weather disturbances, delivery and supplies of materials and tools that are not in accordance with the plan, changes in design and other external, internal factors. For this reason, this study will discuss about controlling project time using the critical chain project management (CCPM) method and 4D building information modeling in high-rise residential building projects, especially in 5-layer basement work. The critical chain project management method eliminates safe time and replaces buffer time. Adding buffer time using the cut and paste method, namely adding a project buffer half the duration of the critical chain (critical chain) at the end of the chain and placing the feeding buffer with half the activity duration to activities on the non-critical chain. Delays in the construction of a 5-layer basement usually include changes in the level of soil surface conditions, the stability of the excavated soil during the secant pile excavation period as a retaining wall as deep as -17,350 m below the ground level. The results of this study can optimize the duration of the implementation with the final completion time of the structural work faster than 432 working days to 293 work days of implementation so that the time efficiency is 32,17%.

Influence of Buffer Size change in Critical Chain Scheduling: Case Study

Performing the Critical Chain Scheduling (CCS) and Buffer Management (BM) in project management has recently risen as one of the most popular project management approaches. The critical Chain Scheduling (CCS) approach is replacing the traditional scheduling method to reduce the uncertainty associated with time schedules. The research highlights the importance of critical chain scheduling in project execution by investigating using buffers in the critical paths and the feeding baths in project management using a real case study. The case study was studied by analyzing the schedule provided and then implementing CCS and BM using four different methods. The methods are cut and paste (C&PM), the root square method (RSEM), the Adaptive procedure with resource tightness, and the Adaptive procedure with network density (APND). The buffer size obtained for each method was determined. From the result got, for project buffer in adaptive approach with network density method yields a larger buffer size compared to the adaptive procedure with resource tightness method. While for feeding buffer also show that APND resulted in a larger buffer size than APRT. Finally, the proposed buffer size was investigated and simulated using the What if approach.

Project buffer sizing and dynamic buffer consumption algorithm in power generation construction

PurposeThe aim of this research is to propose a buffer sizing and buffer controlling algorithm (BSCA) as a heuristic algorithm for calculating project buffer and feeding buffers as well as dynamic controlling of buffer consumption in different phases of a wind power plant project in order to achieve a more realistic project duration.Design/methodology/approachThe BSCA algorithm has two main phases of planning and buffer sizing and construction and buffer consumption. Project buffer and feeding buffers are determined in the planning and buffer sizing phase, and their consumption is controlled in the construction and buffer consumption phase. The heuristic algorithm was coded and run in MATLAB software. The sensitivity analysis was conducted to show the BSCA influence on project implementation. Then, to evaluate the BSCA algorithm, inputs from this project were run through several algorithms recently presented by researchers. Finally, the data of 20 projects previously accomplished by the company were applied to compare the proposed algorithm.FindingsThe results show that BSCA heuristic algorithm outperformed the other algorithms as it shortened the projects' durations. The average project completion time using the BSCA algorithm was reduced by about 15% compared to the previous average project completion time.Originality/valueThe proposed BSCA algorithm determines both the project buffer and feeding buffers and simultaneously controls their consumption in a dynamic way.

Buffer sizing in critical chain project management by network decomposition

Project management organizes about 30% of the world’s economy. Many recent projects apply critical chain project management (CCPM) methodology, which requires the design of project and feeding buffers. Accurate sizing of these buffers is essential, because too small buffers result in emergency procedures to prevent late delivery, whereas too large buffers result in uncompetitive bids and lost contracts. Previous buffer sizing research, focused predominantly on the critical chain, typically results in excessive buffers, and in critical chains being challenged by feeding buffers during planning. This work also performs inconsistently, for example in makespan estimation, at execution. We propose a new procedure for buffer sizing based on network decomposition, which offers logical advantages over previous ones. First, the size of a feeding buffer is determined from all associated noncritical chains. Second, the project buffer incorporates safety margins outside the critical chain by comparing feeding chains with their parallel critical counterparts. Computational testing on a case study of a real project and extensive simulated data shows that our procedure delivers much greater accuracy in estimating project makespan, and smaller feeding buffers. Furthermore, the resulting critical chain is never challenged. Additional benefits include delayed expenditure, and reductions in work-in-process, rework, and multitasking.

A heuristic buffer sizing algorithm for implementing a renewable energy project

The swiftly growing wind farm projects together with the increasing uncertainty of these types of construction projects makes it more probable that projects will face delay. This research aims to introduce a heuristic algorithm to determine the sizes of project buffer and feeding buffers as well as dynamically control buffer consumption, named as Fuzzy Overlapping Buffer Management Algorithm (FOBMA). In this paper, the pentagonal fuzzy numbers were used to determine the appropriate amount of project activity resources. Also, an overlapping method was applied to obtain more realist activity durations. The FOBMA algorithm was compared to other algorithms using the data of 15 real-world wind farm projects as well as 15 randomly generated numerical examples. Moreover, the sensitivity analysis was conducted to validate the performance of the proposed algorithm. The findings demonstrate that the proposed FOBMA algorithm outperforms the other algorithms and yielded more realistic and shorter project duration.

Enhanced enzyme-based CO2 capture in countercurrent packed-bed column reactors

An enhanced CO2 hydration process with human carbonic anhydrase II (hCA II) enzyme immobilized on packing surface and micro-particles dispersed in the liquid phase was proposed. This innovative hybrid enzymatic process was simulated in a countercurrent packed-bed column reactor via an unsteady-state, isothermal, 3-D model including continuity, momentum and species (including the biocatalytic micro-particles) balance equations in the liquid and gas phases, filtration equation describing the accumulation of biocatalytic micro-particles in packed bed, chemical reaction and diffusion in hCA II enzyme washcoat and liquid film. In the hybrid enhanced immobilized enzyme CO2 capture system, hCA II enzyme supported on the surface of micro-particles works as a free solution-phase enzyme, which instantaneously catalyzes CO2 hydration reaction and upgrades significantly CO2 conversion, particularly in the region where the enzymatic process with immobilized hCA II enzyme on the packing surface is strongly limited by the diffusion. The impact of hCA II enzyme immobilized on the micro-particles surface is more important when the foremost amount of hCA II enzyme is immobilized on the packing via larger washcoat layers with enhanced mass transfer resistance, at larger feed buffer concentration and lower thermodynamic dissociation constant of the protonated acid form of buffer. Enhanced CO2 hydration process provide a reasonable CO2 conversion at a much lower liquid velocity and permits to significantly downgrade the height of the packed bed. These immobilized enzyme CO2 capture systems intend to maximize the mass transfer in packed-bed column reactors to expand the degree of utilization of the large hydration turnover of hCA II enzyme.