scholarly journals A next step in disruption management: combining operations research and complexity science

2021 ◽  
Author(s):  
Mark M. Dekker ◽  
Rolf N. van Lieshout ◽  
Robin C. Ball ◽  
Paul C. Bouman ◽  
Stefan C. Dekker ◽  
...  
Keyword(s):  
Operations Research ◽  
Complexity Science ◽  
Rolling Stock ◽  
Accurate Information ◽  
Disruption Management ◽  
Railway Systems ◽  
Decentralized Decision Making ◽  
Control Situations ◽  
Management Techniques ◽  
The Impact

AbstractRailway systems occasionally get into a state of being out-of-control, meaning that barely any train is running, even though the required resources (infrastructure, rolling stock and crew) are available. Because of the large number of affected resources and the absence of detailed, timely and accurate information, currently existing disruption management techniques cannot be applied in out-of-control situations. Most of the contemporary approaches assume that there is only one single disruption with a known duration, that all information about the resources is available, and that all stakeholders in the operations act as expected. Another limitation is the lack of knowledge about why and how disruptions accumulate and whether this process can be predicted. To tackle these problems, we develop a multidisciplinary framework combining techniques from complexity science and operations research, aiming at reducing the impact of these situations and—if possible—avoiding them. The key elements of this framework are (i) the generation of early warning signals for out-of-control situations, (ii) isolating a specific region such that delay stops propagating, and (iii) the application of decentralized decision making, more suited for information-sparse out-of-control situations.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

THE IMPACT OF WORLD WAR II ON COST ACCOUNTING AT THE SPERRY CORPORATION

2003 ◽  
Vol 30 (2) ◽  
pp. 67-104 ◽  
Author(s):  
Richard K. Fleischman ◽  
R. Penny Marquette
Keyword(s):  
World War Ii ◽  
Performance Management ◽  
Scientific Management ◽  
World War ◽  
Military Contractors ◽  
Management Techniques ◽  
Cost Awareness ◽  
The Impact ◽  
Positive Effect ◽  
The U.S

The impact of World War II on cost accountancy in the U.S. may be viewed as a double-edged sword. Its most positive effect was engendering greater cost awareness, particularly among companies that served as military contractors and, thus, had to make full representation to contracting agencies for reimbursement. On the negative side, the dislocations of war, especially shortages in the factors of production and capacity constraints, meant that such “scientific management” techniques as existed (standard costing, time-study, specific detailing of task routines) fell by the wayside. This paper utilizes the archive of the Sperry Corporation, a leading governmental contractor, to chart the firm's accounting during World War II. It is concluded that any techniques that had developed from Taylorite principles were suspended, while methods similar to contemporary performance management, such as subcontracting, emphasis on the design phase of products, and substantial expenditure on research and development, flourished.

scholarly journals The impact of decentralized decision-making on student outcomes and teacher quality: Evidence from Colombia

2021 ◽  
Vol 141 ◽  
pp. 105378
Author(s):  
Gregory Elacqua ◽  
Isabela Munevar ◽  
Fabio Sanchez ◽  
Humberto Santos
Keyword(s):  
Decision Making ◽  
Teacher Quality ◽  
Student Outcomes ◽  
Decentralized Decision Making ◽  
The Impact ◽  
Quality Evidence

scholarly journals Integrated, Speckle-Based Displacement Measurement for Lateral Scanning White Light Interferometry

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2486
Author(s):  
Gert Behrends ◽  
Dirk Stöbener ◽  
Andreas Fischer
Keyword(s):  
White Light ◽  
Lateral Displacement ◽  
Displacement Measurement ◽  
Accurate Information ◽  
White Light Interferometry ◽  
Fully Integrated ◽  
Speckle Correlation ◽  
Dsc Measurements ◽  
Scanning White Light Interferometry ◽  
The Impact

Lateral scanning white light interferometry (LSWLI) is a promising technique for high-resolution topography measurements on moving surfaces. To achieve resolutions typically associated with white light interferometry, accurate information on the lateral displacement of the measured surface is essential. Since the uncertainty requirement for a respective displacement measurement is currently not known, Monte Carlo simulations of LSWLI measurements are carried out at first to assess the impact of the displacement uncertainty on the topography measurement. The simulation shows that the uncertainty of the displacement measurement has a larger influence on the total height uncertainty than the uncertainty of the displacing motion itself. Secondly, a sufficiently precise displacement measurement by means of digital speckle correlation (DSC) is proposed that is fully integrated into the field of view of the interferometer. In contrast to externally applied displacement measurement systems, the integrated combination of DSC with LSWLI needs no synchronization and calibration, and it is applicable for translatory as well as rotatory scans. To demonstrate the findings, an LSWLI setup with integrated DSC measurements is realized and tested on a rotating cylindrical object with a surface made of a linear encoder strip.

scholarly journals Ranking the critical sections of railway networks

2020 ◽  
pp. 095440972092568
Author(s):  
Ratthaphong Meesit ◽  
John Andrews
Keyword(s):  
Network Flow ◽  
Topological Analysis ◽  
Preventive Strategy ◽  
Railway Network ◽  
Macroscopic Models ◽  
Railway Systems ◽  
Railway Networks ◽  
Network Simulation Model ◽  
The Impact ◽  
Critical Sections

Railway systems are now facing an increasing number of threats such as aging infrastructures and climate changes. The identification of critical network sections provides infrastructure managers with the ability to understand the impact of a disruption and creates a suitable preventive strategy to counter such threats. To this end, various vulnerability analysis methods have been proposed for railway networks. Two main types of methods, network topological analysis and network flow-based analysis, have been developed. Both approaches are constructed based on macroscopic models, which take only some railway properties such as network structure, train and passenger flow into account. Thus, the results obtained are high level approximations. This study proposes a new analysis method, which is developed based on the stochastic-microscopic railway network simulation model. The method can be applied to identify the critical sections of a railway network. The effect of impact levels and occurrence times of a disruption on the network section criticality is presented. An application of the proposed model is demonstrated using the Liverpool railway network in the UK.

The Effect of Friction Modifiers on Wheel/Rail Isolation

2008 ◽  
Author(s):  
E. A. Gallardo Hernandez ◽  
J. Cotter ◽  
R. Lewis ◽  
D. T. Eadie
Keyword(s):  
Input Voltage ◽  
Electrical Circuit ◽  
Friction Modifiers ◽  
Friction Modifier ◽  
Contact Impedance ◽  
Static Tests ◽  
Railway Systems ◽  
Significant Difference ◽  
Track Circuit ◽  
The Impact

Train detection, for signalling purposes, is often by means of track circuits. Signalling block occupancy is triggered by the wheelset of the train ‘shorting out’ the track circuit, i.e. the wheels and axle act as a shunt. Contamination on the track such as ballast dust, rust, oil, or leaves as well as substances designed to improve train operation such as friction modifiers or sand may cause the contact between the wheelsets and the track to be compromised, inhibiting train identification. In previous work a twin disc approach has been used to study the effect of sand (used to improve adhesion) and leaves on wheel/rail isolation. Friction modifiers are of significant current interest in wheel/rail research. Introducing a new material into the tread/top of rail interface can raise questions about the impact on signalling systems. Although no significant effects have been observed in practical operation on a range of railway systems, the intention in this work was to evaluate conductance between wheel and rail in a more controlled and systematic fashion using the previously established methodology. Using the twin disc technique, friction modifier, in the form of a solid stick, was applied using a spring loaded device to the rotating wheel disc to generate a visible film. Tests were run to measure contact impedance at typical loads and slips. Static tests were also carried out using discs pre-conditioned with a friction modifier film. The electrical circuit used was a modified simplified simulation of audio frequency track circuit. No significant difference was observed in the measured impedance for dry conditions with no friction modifier, versus tests where friction modifier was applied, regardless of percentage slip or input voltage. The analysis suggests that the introduction of friction modifier into the existing wheel/rail interfacial film does not result in increased impedance with all other factors being equal.

scholarly journals Graceful extensibility in asset management: extending the capacity to adapt in managing cyber-physical railway systems

2021 ◽  
Author(s):  
Jan-jaap Moerman ◽  
Jan Maarten Schraagen ◽  
Jan Braaksma ◽  
Leo van Dongen
Keyword(s):  
Asset Management ◽  
Adaptive Systems ◽  
New Technologies ◽  
Autonomous Driving ◽  
Cyber Physical Systems ◽  
Transportation Systems ◽  
Rolling Stock ◽  
Railway Transportation ◽  
Physical Systems ◽  
Railway Systems

AbstractGraceful extensibility has been recently introduced and can be defined as the ability of a system to extend its capacity to adapt when surprise events challenge its boundaries. It provides basic rules that govern adaptive systems. Railway transportation systems can be considered cyber-physical systems that comprise interacting digital, analog, physical, and human components engineered for safe and reliable railway transport. This enables autonomous driving, new functionalities to achieve higher capacity, greater safety, and real-time health monitoring. New rolling stock introductions require continuous adaptations to meet the challenges of these complex railway systems as an introduction takes several years to complete and deals with changing stakeholder demands, new technologies, and technical constraints which cannot be fully predicted in advance. To sustain adaptability when introducing new rolling stock, the theory of graceful extensibility might be valuable but needs further empirical testing to be useful in the field. This study contributes by assessing the proto-theorems of graceful extensibility in a case study in the railway industry by means of adopting pattern-matching analysis. The results of this study indicate that the majority of theoretical patterns postulated by the theory are corroborated by the data. Guidelines are proposed for further operationalization of the theory in the field. Furthermore, case results indicate the need to adopt management approaches that accept indeterminism as a complement to the prevailing deterministic perspective, to sustain adaptability and deal effectively with surprise events. As such, this study may serve other critical asset introductions dealing with cyber-physical systems in their push for sustained adaptability.

The Role of Financing Higher Education in Nigerian Universities in Achieving Sustainable Development

2021 ◽  
Vol 4 (4) ◽  
pp. 551-578
Author(s):  
Samir Mohamad Hassan
Keyword(s):  
Higher Education ◽  
Sustainable Development ◽  
Private University ◽  
Accurate Information ◽  
Community Initiatives ◽  
Higher Education Financing ◽  
The University ◽  
Financing Higher Education ◽  
The Impact

The current study aims to identify the role of financing higher education in Nigerian universities in the state of Kano and its impact on sustainable development. The study problem lies in the low funding of higher education in Nigerian universities, which will negatively affect the sustainability of higher education and sustainable development. The importance of the study is highlighted by highlighting the importance of financing higher education in Nigerian universities and the sources of obtaining this funding as one of the most important factors through which students can complete their studies. The study followed the qualitative approach with the aim of obtaining more accurate information about traditional higher education financing sources and its impact on the sustainability of education and achieving sustainable development. The study population reached the number of three Nigerian universities, which are a governmental, federal and private university, to learn about the impact of financing higher education in Nigerian universities on sustainable development. The sample of the study was about three out of five of those responsible for financing higher education in Nigerian universities. Also, the study followed unstructured or open interviews in order to obtain more information about financing higher education and whether or not it is suitable for the idea of a monetary endowment. The results of the study showed that the sources of financing for higher education in traditional Nigerian universities are varied, including what can be obtained through the endowment and donations fund that can be made through community initiatives, and the results of the study also indicated that the idea of a monetary endowment faces great challenges in its application, so the idea is subject to acceptance and rejection. According to the nature of the university and the nature of the subjects taught. The study recommended the necessity of expanding the study of the impact of financing higher education in Nigerian universities by expanding the scope of study to include all Nigerian states.

Nutzung von Flexibilitätspotenzialen im Störungsmanagement*/Potentials of flexibility in the disruption management of large-scale product assembly

2016 ◽  
Vol 106 (09) ◽  
pp. 631-636
Author(s):  
H. Prinzhorn ◽  
M. Zenker ◽  
R. Sporrer ◽  
P. Prof. Nyhuis
Keyword(s):  
Production System ◽  
Large Scale ◽  
Disruption Management ◽  
Short Term ◽  
The Impact ◽  
Product Assembly ◽  
Term Response

Die hohe Störfanfälligkeit bei der Montage großskaliger Produkte verlangt eine kurzfristige Auswahl von Maßnahmen zur Reaktion auf Störungen, um Auswirkungen wie Lieferterminverspätungen oder Auslastungsverluste zu reduzieren. Die Nutzung von Flexibilitätspotenzialen eines Produktionssystems stellt einen Ansatz dar, um diese Herausforderung zu bewältigen. Dieser Fachbeitrag zeigt auf, welche Flexibilitätspotenziale in diesem speziellen Umfeld zur Verfügung stehen und genutzt werden können.   Assembling large-scale products involves frequent process interruptions why in order to reduce the impact of interruptions, a short-term response is necessary to reduce delivery delays and idle times of resources. An approach for challenge this represents the flexibility of a production system. Regarding the environment of large-scale product assembly, it has to be shown which potentials of flexibility are able to use in a short-term manner.

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