Linear Schedule Research Articles

Alternatives to Paying Child Benefit to the Rich: Means‐Testing or Higher Tax?

AbstractThere appears to be a general movement away from universal child benefits and towards means‐testing. In the present article we argue that instead of suppressing the labour supply of middle‐income parents by withdrawing the transfer as a function of income, one should consider the alternative of financing a generous universal child benefit by increasing taxation of income. The implications of means‐testing compared with a tax‐financed universal alternative are discussed analytically in a piecewise linear schedule and by combining information from behavioural and non‐behavioural micro‐simulation models. Our results provide support for making child benefit universal instead of means‐tested.

Integrating critical chain project management with last planner system for linear scheduling of modular construction

PurposeThe purpose of this paper is to present a new method for project tracking and control of integrated offsite and onsite activities in modular construction considering practical characteristics associated with this type of construction.Design/methodology/approachThe design embraces building information modelling and integrates last planner system (LPS), linear scheduling method (LSM) and critical chain project management (CCPM) to develop tracking and control procedures for modular construction projects. The developed method accounts for constraints of resources continuity and uncertainties associated with activity duration. Features of proposed method are illustrated in a case example for tracking and control of modular projects.FindingsComparison between developed schedule and Monte Carlo simulation showed that baseline duration generated from simulation exceeds that produced by developed method by 12% and 10% for schedules with 50% and 90% confidence level, respectively. These percentages decrease based on interventions of members of project team in the LPS sessions. The case example results indicate that project is delayed 5% and experienced cost overrun of 2.5%.Originality/valueDeveloped method integrated LPS, LSM and CCPM while using metrics for reliability assessment of linear schedules, namely, critical percent plan complete (PPCcr) and buffer index (BI). PPCcr and BI measure percentage of plan completion for critical activities and buffer consumption, respectively. The developed method provides a systematic procedure for forecasting look-ahead schedules using forecasting correction factor Δt and a newly developed tracking and control procedure that uses PPCcr and BI. Quantitative cost analysis is also provided to forecast and monitor project costs to prove the robustness of proposed framework.

Optimizing adiabatic quantum pathways via a learning algorithm

Designing proper time-dependent control fields for slowly varying the system to the ground state that encodes the problem solution is crucial for adiabatic quantum computation. However, inevitable perturbations in real applications demand us to accelerate the evolution so that the adiabatic errors can be prevented from accumulation. Here, by treating this trade-off task as a multiobjective optimization problem, we propose a gradient-free learning algorithm with pulse smoothing technique to search optimal adiabatic quantum pathways and apply it to the Landau-Zener Hamiltonian and Grover search Hamiltonian. Numerical comparisons with a linear schedule, local adiabatic theorem induced schedule, and gradient-based algorithm searched schedule reveal that the proposed method can achieve significant performance improvements in terms of the adiabatic time and the instantaneous ground-state population maintenance. The proposed method can be used to solve more complex and real adiabatic quantum computation problems.

Alternatives to Paying Child Benefit to the Rich: Means Testing or Higher Tax?

Transferring public benefits to people in no need of them appears to be a waste of public money. Thus, there seems to be support for a move away from universal child benefits and towards means testing. This study presents a critique of this overly-simplistic view and proposes a very simple alternative: instead of withdrawing the transfer as a function of income, which raises marginal tax rates for low and middle income parents, with accompanying detrimental effects on labour supply, redistribution can be achieved by an ambitious universal schedule financed by increased income taxation of the rich. The role of the child benefit is discussed analytically in a piecewise linear schedule. Moreover, the argument is illustrated with reference to the design of the child benefit scheme for Norway, demonstrating the labour supply/redistribution trade-offs of the alternatives by results from simulation models.

Acceleration of repetitive units in construction projects using line-of-balance and linear scheduling with singularity function

Construction managers usually demand to increase the speed of completion of projects to avoid the penalties, to get the bonus from the owner. They plan and control qualitative and quantitative measures for the successful projects. Generally acceleration measures are followed to increase the speed of delivery of the project. Repetitive units in projects plays an important role in modern world such that most of the residential villa projects have some repetitive nature. This paper proposes a method for the acceleration of repetitive units in project by line-of-balance and linear scheduling with singularity function. Line-of-balance method is used for the programming and control of repetitive projects. Linear schedule is focused on the time-amount relationship and progress of the work. Singularity functions were previously used for the analysis of structures and lately applied for scheduling. Linear schedules associate the information on amount of work and time for each activity. This paper put forward a relationship between production rate, duration of completion of project and number of units. It helps to determine the required production rate to complete a particular number of units in a given duration. The analysis of repetitive units in project has been done, and the general equations are formulated for connecting the duration of project, total number of units, duration required for any activity and number of units completed.

On Belief Singularity and the Optimality of Deductible Indemnity Schedules

In Ghossoub (2019), we studied a problem of optimal insurance design under belief heterogeneity. We examined the effect of the divergence in beliefs, and the singularity between the beliefs, on optimal indemnities; and we provided a closed-form characterization of optimal indemnity schedules. In this paper, we build upon the work of Ghossoub (2019) and introduce a belief singularity metric to examine the effect of the level of singularity between the beliefs on the shape of optimal indemnity schedules. Our main result shows that for any level x of belief singularity with respect to the insurer's belief Q, there exists a probability measure P exhibiting a level x of belief singularity with respect to Q, such that an optimal indemnity for a decision maker with belief P is a linear deductible with Q-probability 1, and full insurance with Q-probability 0. In this sense, we show that from the perspective of the insurer, linear deductible indemnity schedules are robust to belief singularity, which gives a possible explanation of the popularity of these contracts in practice.

Robust quantum control for adiabatic quantum computation

Properly designed control has been shown to be particularly advantageous for improving AQC accuracy and time complexity scaling. Here, an \emph{in situ} quantum control optimization protocol is developed to indirectly optimize state fidelity without knowledge of the instantaneous spectral gap or the computational solution. The protocol is shown to converge to analytically-derived time-optimal controls for Grover's search algorithm. Furthermore, the protocol is utilized to explore optimized control trajectories for the Maximum 2-bit Satisifiability (MAX 2-SAT) problem, where appreciable improvement in fidelity and the minimum spectral gap over a linear schedule is observed. The approach is also shown to be robust against system model uncertainties (unitary control errors). This method is designed to enable robust control optimization on existing quantum annealing hardware and future AQC processors.

The effect of compression rate and slope on the incidence of symptomatic Eustachian tube dysfunction leading to middle ear barotrauma: a Phase I prospective study

Symptomatic Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are the most common reported complications during hyperbaric oxygen (HBO2) treatment. There is no standardized rate of compression (ROC) reported to decrease the incidence rates of ETD and MEB during hyperbaric treatments. Few studies actually demonstrate that the ROC decreases the incidence of ETD or MEB. Our study was designed to determine an optimal hyperbaric chamber compression rate that might reduce the incidence of symptomatic ETD leading to MEB during the compression phase of treatment in a multiplace hyperbaric chamber. Data was collected prospectively over 2,807 elective patient treatments compressed using a U.S. Navy Treatment Table 9 (USN TT9) with a modified ROC. ROC was assigned using two variables, time (10 vs.15 minutes) and slope (linear vs. non-linear compression). Patients were exposed to all four compression schedules in a consecutive daily fashion. We recorded any patient requiring a stop during initial compression due to ear discomfort. Anyone requiring a stop was evaluated post treatment for MEB. Findings were compared to our standard 10-minute linear ROC. Evaluation of the tympanic membrane was accomplished using video otoscopy. Barotrauma when present was classified using both the Teed and O'Neill grading systems. Data was analyzed using basic statistical methods. When comparing four different rates of compression during an elective USN TT9 in a multiplace (Class A) chamber there is a decreased incidence for symptomatic ETD when using a 15-minute linear compression schedule (p-value ⟨0.05). Using a 15-minute linear compression schedule is associated with less symptomatic ETD and less MEB when performing an elective 45 fsw (USN TT9) hyperbaric treatment in a Class A chamber. Asymptomatic ETD and MEB were not considered in this study.

İNŞAAT İŞLERİNİN İŞ PROGRAMINA BAĞLI NAKİT AKIŞI DEĞİŞKENLİĞİNİN SAPTANMASI VE DÜZENLENMESİ

İnşaat projesinin yapım süresi ve maliyeti inşaat öncesinde hazırlanan malzeme tedariki ve metraj verilerine dayanarak oluşturulan iş programı ve maliyet analizleri temel alınarak tahmin edilir. İnşaat sürecinde öngörülemeyen etkenler nedeniyle iş programında ve maliyetlerde değişiklikler meydana gelebilir. Bu durum, nakit akışını etkiler. İnşaat sırasındaki iş yoğunluğu nedeniyle nakit akışının güncellemesinin ihmali, gelir gider dengesinin önceden bilinememesine neden olacak ve inşaatın finansmanı üzerinde önemli sorunlar doğurabilecektir. Bu çalışmada, belirtilen sorunların oluşmaması ve güncel verileri kullanarak en doğru ve güncel nakit akışı elde etmek için hakediş hesaplamalarını doğrudan iş programı ile ilişkilendirerek hesaplayan bir model geliştirilmiştir. Bunun için tüm metraj hesaplarında işlem adımları formülleştirilmiş ve formüller hesap cetveli uygulamasında tanımlanmıştır. Malzeme tedariki dâhil metraj verileri ile iş kalemlerinin işçilik ihtiyaçları ve süreleri belirlenmiştir. Doğrusal iş programı ile oluşturulan iş planından aktivitelerin başlangıç ve bitiş süreleri elde edilmiştir. Aktivitelerin maliyetleri birim fiyat analizleri ile belirlenmiş ve günlük gerçekleşen inşaat işleri ve harcamaları hesaplanmıştır. Aktivite sürelerinde olabilecek değişiklikler, iş programı ile birlikte güncellenmekte ve insan müdahalesi olmadan gerçekleşen kısma ait hak ediş ve kalan imalat bedeli yeniden hesaplanmaktadır. Hesaplamaların, tüm müteahhitlerin uygulayabileceği biçimde gösterilebilmesi için hesap cetveli uygulaması şeklinde tasarlanmıştır. Bu uygulama sayesinde müteahhitler inşaat işlerinin nakit akışını anlık güncelleyebilecek ve ileride oluşabilecek olumsuzlukları önceden fark edip önlem alabileceklerdir.

Zero-correlation attacks on tweakable block ciphers with linear tweakey expansion

The design and analysis of dedicated tweakable block ciphers is a quite recent and very active research field that provides an ongoing stream of new insights. For instance, results of Kranz, Leander, and Wiemer from FSE 2017 show that the addition of a tweak using a linear tweak schedule does not introduce new linear characteristics. In this paper, we consider – to the best of our knowledge – for the first time the effect of the tweak on zero-correlation linear cryptanalysis for ciphers that have a linear tweak schedule. It turns out that the tweak can often be used to get zero-correlation linear hulls covering more rounds compared to just searching zero-correlation linear hulls on the data-path of a cipher. Moreover, this also implies the existence of integral distinguishers on the same number of rounds. We have applied our technique on round reduced versions of Qarma, Mantis, and Skinny. As a result, we can present – to the best of our knowledge – the best attack (with respect to number of rounds) on a round-reduced variant of Qarma.

PEMODELAN PENJADWALAN LINIER DENGAN ALOKASI SUMBER DAYA MANUSIA PADA PROYEK PERUMAHAN

Metode penjadwalan linier cocok untuk proyek dengan aktivitas sederhana, dan repetitif dengan jumlah unit yang tipikal, seperti proyek jalan, irigasi, tunnel, apartment, dan perumahan sederhana. Pada penelitian ini dilakukan pemodelan penjadwalan linier proyek pembangunan perumahan sebanyak 50 unit tipikal. Simulasi alokasi sumber daya manusia dan penggunaan buffer agar penggunaan sumber daya manusia dapat seefisien mungkin.
 Hasil penelitian diperoleh bahwa simulasi ke-8 dengan menggunakan buffer memiliki durasi 314 hari dengan 18 kelompok kerja, apabila dibandingkan dengan simulasi ke-9 tanpa menggunakan buffer memiliki durasi 180 hari dan idle time 134 hari inefisiensi 1522 orang hari.
 
 Linear scheduling method is suitable for projects with repetitive activities, as well as tipical mass product units such as a road, apartment, and residential housings. In this research linear schedule modeling was carried out on residential typical housings project of 50 units. The simulation of linear scheduling is to minimize the idle times by using time buffers and human resources allocation so that the usage of human resources can be as efficient as possible.
 The research findings show that the 8th simulation by using buffers has a project duration of 314 days were chosen with 18 working groups, compares to 9th simulation without buffers that has a duration of 180 days and 134 days of idle time which with 1522 man day of inefficient.

Optimal Insurance Without the Nonnegativity Constraint on Indemnities: Ambiguity and Belief Heterogeneity

In Arrow's (1971) classical problem of optimal insurance design, a linear deductible schedule is optimal for an Expected-Utility (EU) maximizing decision maker (DM), if the premium depends on the indemnity's actuarial value, if the DM and the insurer share the same probabilistic beliefs about the realizations of the random loss, and under the classical constraints that, in each state of the world, the indemnity is nonnegative and does not exceed the value of the loss. Raviv (1979) re-examined Arrow's problem and concluded that the presence of a deductible is due to both the nonnegativity constraint on the indemnity and the variability in the cost of insurance. In an effort to test this statement, Gollier (1987) relaxes the nonnegativity constraint and argues that the existence of a deductible is only due to the variability in the cost of insurance. In this paper, we test whether the intuition behind Gollier's result still holds under more general preferences for the DM and the insurer. We consider a setting of ambiguity (one-sided and then two-sided) and a setting of belief heterogeneity. We drop the nonnegativity constraint and assume no cost (or a fixed cost) to the insurer, and we derive closed-form analytical solutions to the problems that we formulate. In particular, we show that an optimal indemnity (resp., retention) no longer includes a deductible provision (resp., is not equal to the realized loss). Moreover, the optimal indemnity (resp., retention) can be negative (resp., higher than the realized loss) for small values of the loss, or in case of no loss. This is in line with the intuition behind Gollier's finding in the case of belief homogeneity and no ambiguity.

Precedence permutation patterns creating criticality constellations: Exploring a conjecture on nonlinear activities with continuous links

Abstract The inaugural challenge of the 2016 Creative Construction Conference has posed two related questions on how many possible criticality constellations with different behaviors for delays and acceleration exist and how said constellations can occur for nonlinearly and monotonously progressing activities that have continuous relations. This paper systematically solves these questions by performing a thorough literature review, assembling theoretical foundations for link constellations, performing a computer simulation of all possible permutations, and providing a mathematical proof by contradiction. It is found that (for the initially assumed self-contained activities in a network schedule that exhibit only a linearly growing production), three newly hypothesized criticality constellations cannot exist. Nonlinear activity constellations with diverging or converging relative pro­ductivities are examined next. Lags in networks become buffers in linear schedules. It is found that a nonlinear curvature of the progress may induce middle-to-middle relations besides those between start and finish. If multiple curvatures are allowed, then partial segments can form relations, which increase the number of criticality constellations. This paper is extended from the 2017 Procedia Engineering conference version.

Identification of duration construction of combined foundation

The method for determining the duration of a combined foundation device, which is constructed in several stages, is considered in the article. The main stages include the construction of structures and the regulation of the stress-strain state of the soil base, which is carried out by pressing it. Pressurization is carried out during the construction of the building. On an example of construction of the linear schedule the mutual coordination of works of each stage during building of a building is resulted. The possibility of varying the time parameters of the network model is presented depending on the parameters of the crimping process. Between the late and early beginnings of work there is a common time reserve, which is part of the technological break. The authors present empirical data on the actual duration of concreting of grillage of combined foundations. The study of time parameters of technological processes was based on such methods of observation as timekeeping, photo-timing and video and photo-fixation. The measurements were carried out during the construction of the residential complex «Neighbors» in Tyumen. The scope of research included the study of labor costs of the team, consisting of seven concrete workers. The investigated technological process of concreting consistently included the reception and direction of the concrete mix, laying, leveling and compacting the mixture, smoothing and smoothing the grillage surface. Based on the data obtained, the dependencies of the average duration of concrete work on the volume of the concrete mix laid in the cells (shells) are revealed. The comparison of work durations on both foundations is made. Actual work is determined and work time standards are established, allowing to organize concrete works with sufficient precision when drawing up calendar plans within the framework of working out of projects for the production of works. This article is made in the framework of the dissertation research by co-author Volosiuk D.V.

Updating Linear Schedules with Lowest Cost: a Linear Programming Model

Many civil engineering projects involve sets of tasks repeated in a predefined sequence in a number of work areas along a particular route. A useful graphical representation of schedules of such projects is time-distance diagrams that clearly show what process is conducted at a particular point of time and in particular location. With repetitive tasks, the quality of project performance is conditioned by the ability of the planner to optimize workflow by synchronizing the works and resources, which usually means that resources are planned to be continuously utilized. However, construction processes are prone to risks, and a fully synchronized schedule may expire if a disturbance (bad weather, machine failure etc.) affects even one task. In such cases, works need to be rescheduled, and another optimal schedule should be built for the changed circumstances. This typically means that, to meet the fixed completion date, durations of operations have to be reduced. A number of measures are possible to achieve such reduction: working overtime, employing more resources or relocating resources from less to more critical tasks, but they all come at a considerable cost and affect the whole project. The paper investigates the problem of selecting the measures that reduce durations of tasks of a linear project so that the cost of these measures is kept to the minimum and proposes an algorithm that could be applied to find optimal solutions as the need to reschedule arises. Considering that civil engineering projects, such as road building, usually involve less process types than construction projects, the complexity of scheduling problems is lower, and precise optimization algorithms can be applied. Therefore, the authors put forward a linear programming model of the problem and illustrate its principle of operation with an example.

Scheduling Optimization of Linear Schedule with Constraint Programming

AbstractIn recent decades, construction project scheduling optimization has received extensive attention from the research community. However, the most commonly used scheduling approach, the critical path method, is often inapplicable to transportation‐type linear projects. Recently, the linear scheduling method (LSM) has demonstrated many advantages for such projects and has become a popular research subject. As a relatively novel scheduling method, LSM requires further improvement, as there are restrictions associated with the scheduling/optimization of linear projects. By analyzing results from previous studies, we propose a unique three‐element mode, a description method for LSM's logical relationships and constraints system. An LSM‐based scheduling optimization model based on constraint satisfaction problems and constraint programming is then proposed that could be used in classical scheduling optimization problems with flexibility, practicability, and solution superiority. The proposed model is verified using three practical transportation construction projects. Verification under six optimization scenarios demonstrates the advantages of our approach.

Precedence Pattern Permutations Creating Criticality Constellations: Exploring a Conjecture on Non-linear Activities with Continuous Links

The inaugural challenge of the 2016 Creative Construction Conference has posed two related questions on how many possible criticality constellations with different behavior for delays and acceleration exist and how said constellations can occur for non-linearly and monotonously progressing activities that have continuous relations. This paper systematically solves these questions by performing a thorough literature review, assembling theoretical foundations for link constellations, performing a computer simulation of all possible permutations, and providing a mathematical proof by contradiction. It is found that (for the initially assumed self-contained activities in a network schedule that exhibit only a linearly growing production) the three newly hypothesized criticality constellations cannot exist. Non-linear activity constellations with diverging or converging relative productivities are examined next. Lags in networks become buffers in linear schedules. It is found that a non-linear curvature of the progress may induce middle-to-middle relations besides those between starts and finishes. If multiple curvatures are allowed, then partial segments can form relations, which increases the number of criticality constellations.

The Optimal Earned Income Tax Credit

In this paper we characterize the optimal linear and piecewise linear EITC schedule. In the linear framework we demonstrate that in the presence of unemployment, an increase of social inequality aversion and a decrease in labor aversion both derive in a lower optimal EITC. For the piecewise linear schedule, we show that in most cases the optimal schedule is a triangle, which is at odds with actual policy, that is based on a trapezoid. According to our simulation, the use of a trapezoid instead of a triangle implies a substantial loss in terms of Social Welfare. We show that a trapezoid is optimal only when the wage distribution among the working poor is even, with a discrete jump for higher wage groups. After mimicking the wage distribution in different countries, we show that changes in the share of the very rich have a lower impact on the optimal EITC compared to changes in the wage variance. Finally, we show that the main impact of an increased minimum wage on the optimal EITC schedule is a more pronounced phasing out.

Formulating a linear scheduling development index

Construction projects are criticised for overrunning time and cost. Previous studies have identified ineffective planning and scheduling as the most frequently cited cause of delay. Moreover, earlier research debated that network-based planning methods are not suitable for projects with repeating activities. Linear scheduling was argued to be a better tool for simulating projects with repeating activities, such as railways, tunnels, roads and infrastructure. Research efforts on schedule quality and development measurement were devoted to network-based scheduling methods. This study critically reviews current programme quality evaluation models in the literature; the review outcomes are used in interviews with four industry experts to identify suitable criteria for assessing linear schedules. There were 23 criteria confirmed that were then arranged into six groups. Based on the interviews, a questionnaire was distributed, and responses were obtained from 125 participants. Results indicated a high level of agreement on the importance of the defined criteria. They are subsequently ranked according to relative importance. The results show that contractual measures are ranked highest and duration estimation second. In addition, a relationship between level of knowledge and importance of using linear schedules was identified. The study proposes a framework for assessing development level and quality of linear schedules.

An Integrated Expert System for Linear Scheduling Heavy Earthmoving Operations

Heavy earthmoving operations are repetitive in nature and vulnerable to time-related restraints and uncertainties. Therefore, at the conceptual stage, scheduling these operations can take a linear form, known as linear schedule or line of balance (LOB). In such type of work, generating a preliminary line of balance for variable sequencing of activities is crucial. In this paper, an integrated expert system for determining preliminary linear schedules for heavy earthmoving operations at the conceptual stage is presented. The proposed system incorporates numerous factors that influence the analysis of earthmoving operations, which include geological and topographical parameters used to determine productivity rates at the conceptual stage. Also, the proposed system is capable of automatically generating a line of balance based on a stochastic scheduling technique via the metaheuristic simulated annealing intelligent approach to incorporate randomness and uncertainties in performing the associated activities. A parametric analysis is conducted in order to quantify the system’s degree of accuracy. An actual case project is then utilized to illustrate its numerical capabilities. Generating accurate linear schedules for heavy earthmoving operations at the conceptual design stage is anticipated to be of major significance to infrastructure project stakeholders, engineers, and construction managers by detecting schedule’s conflicts early in order to enhance overall operational logistics.