Teses / dissertações sobre o tema "Punctuality"

Long and frequent train delays, striking many periodically make headlines. The question is raised: what might be done about it? The on-going deregulation of the Swedish railway, with more actors entering the market, contributes to the question's topicality. In this thesis, problems and symptoms concerning punctuality are described and analysed. Herein, punctuality is defined as the extent to which an event takes place when agreed, for example the agreement between passengers and the company selling the ticket, considering the event that the train arrives at a certain time. The terminology in use on punctuality-related entities is floating. Causes for unpunctuality are related to the infrastructure, locomotives, wagons and personnel. Herein, primarily failures related to infrastructure are discussed. Maintenance, i.e. correcting and preventing failures, together with the track, rolling stock, weather, driver, other personnel and the timetable determine how good the punctuality will be. To the ore and steel transports studied it is more important to limit the lengths of the transport times, rather than having high punctuality, i.e. adherence to timetable. Generally, for freight transports it is difficult to give an estimation of the cost for unpunctuality. To find the root cause of a delay is vital, as is identification of symptoms and triggering events, in order to be able to carry out appropriate actions. Often the information needed to do so is lacking in the Ofelia database for infrastructure failures. Comparisons between regions or over time are complexified by the varying policies on how failure coding is to be performed. To improve punctuality by learning from others is made more difficult by e.g. different countries employing different ways of denoting punctuality. In the transport chain of post in Norway, terms related to punctuality varied even more among stakeholders. They considered being informed on estimated time of arrival as important, but getting this information was, despite this, not among the quantified goals. Few requirements were quantified, despite this often being simple to do. The consequences of failure are important to consider, not only e.g. the number of failures. Studying the variation in transport time on different line sections might help in identifying problems, because coding of delays shorter than five minutes is not carried out in the Swedish railway. Such causes of delay include low contact wire voltage, minor problems with locomotives and slippery rails due to leaves on the track. Disadvantageously, this variation is masked in the case of heavy trains or steep and curvy lines. In a studied maintenance organisation, the indicators of maintenance measured the result of the entire maintenance process. In order to manage each sub process better, it is more advantageous to measure the performance of them individually. Considering the specific sub process that decides which maintenance actions are to be carried out, it only uses expenses for the action itself when deciding, not resulting future costs and punctuality. The indicators focus on measuring past performance, not on facilitating planning for the future. A design of information systems facilitating information usage from different functions of the organisation would facilitate informed decisions. Information concerning technology, traffic and economy need to be integrated.<br>Godkänd; 2005; 20061218 (haneit)

Airline schedule punctuality is a complex problem and one of the major concerns of the airline top management. Flight schedule disturbances may occur as delays and/or cancellations. There are many internal and external reasons for delays. These delays may propagate in the aircraft cycles and cause a large schedule disturbance. This may influences passenger satisfaction and airline resources. The objective of this research is to formulate a systematic approach for schedule punctuality which supports management decision making. The punctuality management system is structured to combine all schedule punctuality components, input and output variables. Five models are incorporated in this system. The first model is the disturbance model which generates random delays based on an estimated Lognormal delay distribution function. The delay analysis is carried out from a one year sample of delay statistics in which general, original , reactionary and other delay types are classified. The second model is the recovery model which incorporates the disturbance model with management strategies to determine delay propagation. A PC based simulation model (SKDMOD) is developed as a prototype which integrates disturbance and recovery models using SIMSCRIPT 11.5. 18 management strategies are simulated covering ground times (30, 40 and 50 minutes), maximum delay times to assign spare aircraft (1, 2, 3, 4, 5, and 6 hours) and spare aircraft using part of the domestic network of Saudi Arabia. The third model is the passengers' attitude model which determines the delay impact functions and the maximum passenger revenue loss based on 262 responses from a passenger interview survey. The fourth model is the revenue model which estimates the passengers' revenue loss. The fifth model is the cost model which estimates the extra cost resulting from implementation of the management strategies. All strategies are evaluated to determine the optimum based on profit and profit margin. OPTIM is the optimization program developed to find the optimum strategy(ies). This approach provides a guidelines for the management of punctuality. It integrates all the tools developed in a decision support system framework.

The rail way sector has been losing market, required increased subsidies and failed to generate anticipated rate of return. Therefore there has been a strong interest to measure the performance of railway operators in terms of punctuality. It is evident that In Norway punctuality shows considerable variation; most of the line being in non-optimal condition, speed is frequently reduced. Such speed reductions are often highlighted as major causes of delays. This master thesis studied the actual delays occurring on the parts of the line between Oslo and Trondheim which have speed restrictions. In doing actual time, travel times and speed restriction magnitudes data have been collected along the line. Combining both qualitative and quantitative approach to research the master thesis have mapped and analyzed speed restriction zones along the line. Using restriction mapping, statistical tools and curve fittings, the analysis revealed that as long as there is sufficient data, uniformity and regular fluctuation of the time magnitudes data there is an increasing effect caused and trend displayed on the actual time taken in the presence of the speed restrictions. Furthermore the research has looked in to the magnitude based relationship between the lost time due to restrictions and associated deviations in travel time. These resulted in a strong correlation between deviation of travel time and magnitude of lost time due to restrictions.

In a complex system such as the Norwegian railway network, there are much thatcan affect a trains punctuality. The undertakers strive to achieve higher and higherpunctuality, while the infrastructure owner, Jernbaneverket, strive for minimaldowntime on the railway network. There is collected much data for analysis aboutthe trains run and the infrastructure, in order to achieve higher punctuality and lessdowntime. The users are able to track down the source of delays and find possibleimprovements on the infrastructure, by analyzing and comparing the different datasets collected.There are many users across both different companies and internal divisionsin a company that need to cooperate, due to the size and complexity of a railwaynetwork. The different users have different needs when studying the data sets. Aarea director have the need to see the big picture over time, while a segment directorwants to see every detail within its segment.In this thesis we demonstrate a system that is aware of the different stakeholdersrequirements when presenting data. The system also takes into consideration thestakeholders need for analyzing different types of data, and comparing these.Finally, we conclude how users should be defined within a domain in order tobe aggregated over.

The increasing demand for transportation and sustainability makes railways attractive. The ongoing deregulation of state-owned railways means that many new organisations are entering the railway sector. Hence, reducing railway delays is increasingly important to many stakeholders, including passengers, freight customers, train operating companies, railway infrastructure managers and society in general. Therefore, the study of punctuality and its improvement is essential. The purpose of the research presented in this thesis is to explore and describe information and requirements related to railway punctuality in order to support systematic improvements. The focus is on delay causes related to infrastructure maintenance. To fulfil the stated purpose, punctuality requirements, availability concepts, failure and delay data, as well as maintenance decisions, have been studied via theoretical and empirical approaches. Data was collected through interviews, document studies, archival analysis, observations and experiments. It is found that punctuality requirements and performance are currently expressed in many, hardly commensurable, ways. Hence, it is difficult to compare punctuality data from different railways. This is further complicated by the fact that delay attribution is inconsistently performed. It is also found that there is a lack of data on train traffic and infrastructure, for example, causes of delays. Although the consistency regarding ranking of decision-making criteria is rather high, the consistency of maintenance decisions is rather low. In addition, there are many interacting causes affecting punctuality, including infrastructure, timetable, rolling stock, weather and personnel. It is also found that even though unpunctuality might be explained by unavailability of some parts of the railway system, the concept of availability is not well-established and agreed upon within the railway sector. Based on the research findings, it is proposed that punctuality should be treated as the extent to which an event takes place when agreed, for example, the agreement between a passenger and a train operating company concerning the arrival of a train at a certain time. A number of availability measures for railway are also proposed, partly based on analogies to the power industry. Furthermore, the developed and applied methodologies, based on vignettes and the Analytic Hierarchy Process (AHP), are proposed to support punctuality improvements. To summarise, based on the results of this research, it is possible to improve data collection and recording, select suitable indicators and increase the awareness of the grounds on which decisions are made, all of which contribute to improved punctuality.<br>Den ökande efterfrågan på transporter, helst med låg miljöbelastning, gör järnvägen till ett attraktivt alternativ. I den pågående omregleringen av statliga järnvägar gör många nya aktörer entré i branschen. Att minska järnvägsförseningarna blir allt viktigare för många intressenter, som passagerare, godskunder, tågoperatörer, infrastrukturförvaltare och samhället i stort. Därför är det mycket viktigt att studera de faktorer som påverkar punktligheten.Syftet med forskningen som presenteras i denna avhandling är att undersöka och beskriva information och krav relaterade till punktlighet, i syfte att stödja systematiskt förbättringsarbete. Fokus ligger på förseningsorsaker relaterade till infrastrukturunderhåll. För att uppfylla syftet har punktlighetskrav, tillgänglighetskoncept, data för fel och förseningar, liksom underhållsbeslut, studerats teoretiskt och empiriskt. Datainsamling har skett med intervjuer, dokumentstudier, arkivmaterial, observationer och experiment.I avhandlingen visas att punktlighetsprestation och -krav idag uttrycks på många, knappast jämförbara, sätt. Således är det svårt att jämföra punktlighetsdata, eftersom olika järnvägar presenterar punktlighet på skilda sätt. Detta försvåras dessutom av att förseningsrapporteringen utförs inkonsistent. Det visas också att det saknas data om tågtrafik och infrastruktur som skulle kunna underlätta för förbättringar, även beträffande förseningsorsaker. Även om konsistensen för rangordning av kriterierna för beslutsfattande är god, är konsistensen för underhållsbeslut ganska låg. Dessutom påverkar många interagerande faktorer punktligheten, till exempel infrastruktur, tidtabell, rullande materiel, väder och personal. Det visas också att trots att opunktlighet kan förklaras av otillgänglighet hos enheter i järnvägssystemet, så saknar järnvägssektorn ett allmänt accepterat tillgänglighetsbegrepp.Baserat på forskningsresultaten föreslås att punktlighet definieras som i vilken utsträckning en händelse äger rum när det är överenskommet, till exempel överenskommelsen mellan en passagerare och en tågoperatör beträffande händelsen att ett tåg ankommer vid en viss tidpunkt. Ett antal tillgänglighetsmått för järnvägen föreslås också, delvis baserade på analogier med elkraftsindustrin. De arbetssätt som utvecklats och tillämpats, baserade på scenarier och AHP (Analytic Hierarchy Process), föreslås användas för att stödja punktlighetsförbättringar.Sammanfattningsvis, baserat på resultaten av denna forskning, är det möjligt att förbättra datainsamlingen och registreringen, välja lämpliga indikatorer och öka medvetenheten om använda beslutsgrunder, vilket bidrar till förbättrad punktlighet.<br>Godkänd; 2008; Bibliografisk uppgift: Förbättrad punktlighet : från data till beslut i järnvägsunderhåll; 20080314 (ysko)

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>Este trabalho investiga a questão do tempo na cultura brasileira, mais especificamente, o conceito de pontualidade. Identificaram- se e caracterizaram-se aspectos da (im)pontualidade como fenômeno social partilhado por brasileiros residentes na cidade do Rio de Janeiro. Dado o objetivo de se detectarem as regras implícitas do sistema temporal carioca, mostrou-se relevante o contraste entre a autopercepção e a heteropercepção dos informantes, na medida em que, na sua maioria, eles se percebem como individualmente pontuais, em oposição à imagem genérica de impontual que relacionam ao coletivo, aos brasileiros. Acredita-se que os resultados desse estudo possam oferecer subsídios para uma melhor compreensão a respeito da percepção de pontualidade dos brasileiros, fomentando a reflexão sobre esse tópico por parte do professor de português como segunda língua para estrangeiros e, conseqüentemente, sua discussão em sala de aula. Dada a natureza interdisciplinar do assunto, este estudo realizou-se à luz dos referenciais teóricos das seguintes áreas: Antropologia Lingüística, Antropologia Social, Sociologia, Psicologia Social, Interculturalismo e Cruzamento de Culturas.<br>This work investigates time in the Brazilian culture, more specifically, the concept of punctuality. The author identified and characterized aspects of (un)punctuality as a social phenomenon shared by Brazilians who live in the city of Rio de Janeiro. The aim of this work was to detect the implicit rules in the time marking system in the city of Rio de Janeiro. The contrast between the informants´ self-perception and perception of others proved to be quite relevant since most of them think of themselves as punctual, in opposition to the generic image of unpunctuality associated with the Brazilians collectively considered. The outcomes of this research work will most certainly offer subsidies to a better understanding of the perception of punctuality among Brazilians and will enhance the thinking of teachers of Portuguese as a second language about this topic and consequently foster discussion about it in classroom activities. Considering the interdisciplinary nature of this subject, the study was carried out in the light of theoretical references in the following areas: Linguistic Anthropology, Social Anthropology, Sociology, Social Psychology, Inter-Culturalism and Cultures Crossing.

Banverket (‘the National Swedish Railway Administration') is responsible for management of the infrastructure in Sweden. The main objective of Banverket, stated by the Swedish government, is to assure a cost-effective and long-term provision of transportation for citizens and the business sector. In order to stay competitive with other forms of transportation, the railway needs to be cost-effective and provide reliable service. The reliable service is to a great extent reflected in terms of train punctuality. Railway components in general have a fairly long life, which means that the cost effectiveness of the transportation system is highly dependent on the effectiveness (doing the right things) and the efficiency (doing the things right) of its operation and maintenance process. The purpose of maintenance is to ensure business objectives through the assurance of required technical functions. Maintenance in the railway ensures the function of the systems that are es-sential for the operation of the transportation system. In other words, maintenance is a vital tool for achieving punctuality, which next to safety is Banverket's most important goal area. Developments in sensor technology and in the information and communication technology sector have provided new opportunities to use technology to assess infrastructural and rolling stock conditions. Decision support derived from condition monitoring systems can provide opportunities for improved maintenance management. In other words, condition monitoring can provide conditions for improved maintenance effectiveness and efficiency and hence punctuality. The thesis explores three areas. The first area is the exploration of current train delay statistics, performed in order to assess how the statistics can represent the influence of different factors on punctuality. The second is an exploration of the link between punctuality and maintenance and more specifically condition monitoring. The third area explores current condition monitoring applications at Banverket to form a knowledge foundation for further condition monitoring implementations intended to improve the reliability and hence the punctuality of the transportation system. In the perspective of the studies are important factors for successful applications of condition monitoring technology proposed. These are factors such as knowledge of problem characteristics, information accuracy, measurement limitations and ability to combine condition based maintenance objectives with business objectives etc. Furthermore, are recommendations for future condition monitoring implementations made. These are recommendations for enhancing the condition-based maintenance, which in turn is dependent on applications of condition monitoring. The final discussions are based upon overall experience from working with the material. The discussion links to the initial research problem, whose intension is to widen the horizon of possible condition monitoring applications.<br><p>Godkänd; 2005; 20061213 (haneit)</p>

The airline industry has become more competitive since the introduction of low fare airlines in the 1990s. Thus, requirement of optimized planning is nowadays essential in order to obtain high market shares. The planning behind an airworthy traffic program is complex and includes many different resources, as fleet, crew and maintenance, which have to be synchronized. With a constant risk of unforeseen disruptions and variances in the weather conditions, robustness in form of time buffers are necessary in order to give the system a chance of recovery. Generally, one delay often affects several flights due to the lack of time buffers. In order to achieve cost reductions and to maximize profit, airlines tends to create traffic programs maximizing airborne hours. This report culminates in a conclusion of where and when time buffers, in a cost efficient way, can be added in Scandinavian Airline´s traffic program in order to obtain a higher robustness. This is performed by analyzing historical flight data and by implementing a Monte Carlo simulation.

Absenteeism, lateness, and work performance on the job were investigated. Pre-entry attitudes and self-reported behaviors in the three areas were assessed via RELY, a self-report instrument developed by Kurt Helm (1980). Subjects (N=282) were entry-level stock, bag and clerical personnel for a large grocery store chain. They were 91% Caucasian and 62% male. Results showed significant correlation between three empirically derived scales and criteria: total days absent, total occurrences of lateness, and supervisory performance ratings. However, these findings were considerably weaker under cross-validation. The findings indicate absence-proneness as a tenable concept. Further investigation may find a considerable amount of the variance in attendance to be the result of pre-entry attitudes.

Based on an initiative to increase the punctuality on Swedish railways in the short term, this study on potential for increased punctuality by adjustments in the train time schedule on The Western Main Line was initiated. This was done by examining alternatives with different adjustments based on today’s timetable. The goal with the study was to increase the punctuality for the highspeed trains on The Western Main Line by five percentage points. Additionally, the study had a purpose of testing if the Swiss concept of Taktfahrplan could be applicable on a Swedish railway. The adjustments of the timetable were based on three parameters that have impact on the robustness of a timetable; dwell time, allowance and headway between trains. Those were the parameters that were tested. Based on a literature study and data on today’s delays, punctuality and dwell times for the highspeed trains, the current situation could be analyzed. The analysis showed that the trains of today’s timetable departed densely in the mornings, the biggest amounts of trains were near the big cities, punctuality had improved from 2019 to 2020, problematic points with large delays existed around Hallsberg and Falköping and the performed dwell times were longer than the planned ones for every station. Based on the analysis of today’s situation, three case alternatives as well as an alternative for comparison were created. In case alternative 1, dwell times were extended for the highspeed trains stops, in alternative 2, allowance was added and in alternative 3, headway was extended at the start stations. Time schedules for the alternatives were created in RailSys and were then simulated on a selected stretch with a disturbance filter that was based on real distributions of delay. The results did not show considerable difference in punctuality for the case alternatives. However, alternative 1 and 2 showed improvement, while the punctuality was reduced in alternative 3. A fourth alternative was created, where the two cases that had led to improvement were combined. After simulation of alternative 4, it could be established that it was the case that provided the highest improvement in punctuality. A Taktfahrplan (regular departures and station meetings) was made in RailSys that showed how well such a timetable was applicable for the highspeed trains on The Western Main Line. The results turned out well because meeting spots for these trains, at half hour traffic and the selected stopping patterns, occurred most evidently at Katrineholm C, but also at Södertälje syd, Skövde C and Herrljunga. The conclusions of the study were that none of the alternatives led to a 5-percentage increase in punctuality. However, three cases led to increased punctuality, while one case produced decreased punctuality. The parameters that produced the highest increase in punctuality was the combination of dwell time and allowance adjustments. The consequences of the adjustments were longer planned driving times for the trains and lower capacity utilization on the track. Lastly, it was established that Taktfahrplan was applicable for the highspeed trains on The Western Main Line, but further analysis would be required before implementation, especially with consideration to planning for practical introduction.

Punktlighet är ett viktigt mätetal inom järnvägsindustrin, men också en stor utmaning. Ett övergripande mål i Sverige är att samtliga tåg, både person- och godståg, ska ha en punktlighet på 95% vid slutdestinationen, där tåg som anländer högst fem minuter efter utsatt tid räknas som punktliga. Under 2019 var godstågens punktlighet 77,9%. Försenade godståg innebär stora kostnader i form av kvalitetsavgifter för den part som orsakat förseningen, samhällsekonomiska kostnader samt ett förlorat förtroende för järnvägen där kunder väljer andra transportslag för att garantera att varorna anländer i tid. Syftet med examensarbetet är att identifiera vilka faktorer som påverkar godstågens punktlighet samt att ta fram rekommendationer för hur punktligheten kan förbättras. För att uppfylla examensarbetets syfte delades projektet upp i två delmål som besvarades genom att tillämpa problemlösningsmetodiken DMAIC. Det första delmålet var att identifiera hur godstågens punktlighet påverkades av att avgå utanför utsatt tid. Detta undersöktes genom att jämföra hur godstågens resor förändrades då de avgått punktligt samt tidigare eller senare än planerat. Genom att visualisera hur genomsnittet av respektive resa sett ut och jämföra dessa med varandra kunde det påvisas att avgångstiden inte är den mest betydande faktorn för godstågens punktlighet. Detta för att resan såg liknande ut oavsett då tågen avgick och den totala restiden skiljde sig inte åt nämnvärt. Det framkom även att tåg som avgår punktligt får färre merförseningar än tåg som avgår utanför gränserna för punktliga tåg. Det andra delmålet var att identifiera vad som påverkar godstågens punktlighet längs sträckan. Detta undersöktes genom att studera godstågens tidsavvikelse vid samtliga trafikplatser längs sträckan samt att analysera de orsakskoder som rapporterats in för respektive tågresa. Här påvisades att tågen inte körs enligt framtagen tågplan, vilket påverkar punktligheten negativt. Några identifierade orsaker till detta är att de olika tåguppdragen har olika förutsättningar att köra samma sträcka, trots att de har samma största tillåtna hastighet. Samt att det finns tåguppdrag som systematiskt reducerar den framförda hastigheten på grund av minskad bromsverkan, vilket i sin tur beror på dåliga vagnar eller för långt/tungt tågekipage. Utöver de två delmålen identifierades även att det fanns bristande datakvalitet i den inrapportering av orsakskoder som tillämpas idag. Exempelvis saknades dryga 40 % data för att förklara varför en merförsening uppstått. Examensarbetet resulterade i tre rekommendationer för hur godstågens punktlighet kan förbättras och dessa var: Kontinuerlig dialog mellan berörda parter för att ta fram en mer tillförlitlig tågplan. Systematiska avvikelser från tågplanen ska ha en högre kvalitetsavgift vid förseningar. Förbättra analysunderlaget genom en bättre inrapportering av orsakskoder.<br>Punctuality is an important measurement in the railway industry, but also entails some challenges. In Sweden there is an overall goal that both passenger- and freight trains should have a 95% punctuality when they arrive at their final destination, where trains who arrive at their final destination less than five minutes after scheduled arrival counts as punctual. During 2019 the punctuality for freight trains was 77,9%. Delayed freight trains are connected to large costs for both the railway industry and for the society. The purpose of this master thesis is to identify which factors affect freight train punctuality and to find recommendations on how to improve it. To fulfill this purpose, the project was divided into two milestones that were answered by applying the problem-solving methodology DMAIC. The first milestone was to identify how punctuality was affected by freight trains departing outside of their appointed departure time. This was done by comparing how journeys differentiated when trains departed punctually as well as earlier or later than planned. By comparing these with each other it was proven that departure time is not the most affecting factor when it comes to freight train punctuality. Because each trains journey had a similar pattern regardless of when they departed and the travel time for the trains did not differ significantly. Furthermore, it was found that trains that are punctual at their time of departure have less delays during the trains entire route than trains who depart outside of the time-window for punctual departure.  The second milestone was to identify what affected the freight train punctuality during the trains entire route. This was done by investigating the time deviation for each train at every measurement point during the route and by analyzing the reasons for time deviation. It turned out that the trains did not run according to the set timetable, which affected the punctuality in a negative way. A few identified reasons for this was that different trains had different prerequisites to drive the same route, even though they are planned for the same speed. And that some trains systematically reduced their speed due to a lack of breaking capacity, as a result of the train being too long or heavy. Beyond the two milestones it was identified a lack of data quality in the reporting of reasons for time deviation. For example, about 40 % of data was missing that could have further explained why the trains where delayed.  The master thesis resulted in three recommendations for how freight train punctuality can be improved, and these were: Continuous dialogue between affected parties to make a timetable that is more reliable. Systematic deviations from the timetable should have a higher cost for causing these. Improved data quality for further analysis of why delays occur.

The timetable is an essential part for the operations of railway traffic, and its quality is considered to have large impact on capacity utilization and reliability of the transport mode. The process of generating a timetable is most often a manual task with limited computer aid, and is known to be a complex planning problem due to inter-train dependencies. These inter-train dependencies makes it hard to manually generate feasible timetables, and also makes it hard to improve a given timetable as new conflicts and surprising effects easily can occur. As the demand for railway traffic is expected to continue grow, higher frequencies and more saturated timetables are required. However, in many European countries there is also an on-going public debate on the punctuality of the railway, which may worsen by increased capacity utilization. It is therefore also a need to increase the robustness of the services. This calls for increased precision of both the planning and the operation, which can be achieved with a higher degree of automation. The research in this thesis is aimed at improving the robustness of railway timetables by combining micro-simulation with mathematical optimization, two methods that today are used frequently by practitioners and researchers but rarely in combination. In this research a sequential approach based on simulating a given timetable and re-optimizing it to reduce the weighted sum of scheduled travel time and predicted average delay is proposed. The approach has generated promising results in simulation studies, in which it has been possible to substantially improve the punctuality and reduce the average delays by only increasing the advertised travel times slightly. Further, the results have also indicated a positive socio-economic benefit. This demonstrates the methods potential usefulness and motivates further research.<br>För järnvägen har tidtabellen en central roll, och dess kvalité har stor betydelse för kapacitet och tillförlitlighet. Processen att konstruera en tidtabell är ofta en uppgift som utförs manuellt med begränsat datorstöd och på grund av beroenden mellan enskilda tåg är det ofta ett tidskrävande och svårt arbete. Dessa tågberoenden gör det svårt att manuellt konstruera konfliktfria tidtabeller samtidigt som det också är svårt att manuellt förbättra en given tidtabell, vilket beror på att de är svårt att förutsäga vad effekten av en given ändring blir. Eftersom efterfrågan på järnväg fortsatt förväntas öka, finns det ett behov av att kunna köra fler tåg. Samtidigt pågår det redan i många europeiska länder en offentlig debatt om järnvägen punktlighet, vilken riskeras att försämras vid högre kapacitetsanvändning. Därför finns det även ett behov av att förbättra tidtabellernas robusthet, där robusthet syftar till en tidtabells möjlighet att stå emot och återhämta mindre förseningar. För att hantera denna målkonflikt kommer det behövas ökad precision vid både planering och drift, vilket kan uppnås med en högre grad av automation. Forskningen i denna avhandling syftar till att förbättra robustheten för tågtidtabeller genom att kombinera mikro-simulering med matematisk optimering, två metoder som redan används i hög grad av både yrkesverksamma trafikplanerare och forskare men som sällan kombineras. I den här avhandlingen förslås en sekventiell metod baserad på att simulera en given tidtabell och optimera den för att minska den viktade summan av planerad restid och predikterad medelförsening. Metoden har visat på lovande resultat i simuleringsstudier, där det har varit möjligt att uppnå en väsentligt bättre punktlighet och minskad medelförsening, genom att endast förlänga de planerade restiderna marginellt. Även förbättrad samhällsekonomisk nytta har observerats av att tillämpa den föreslagna metoden. Sammantaget visar detta metodens potentiella nytta och motiverar även fortsatt forskning.<br><p>QC 20191112</p>

In der vorliegenden Arbeit wurden Verfahren entwickelt und getestet, um Prioritätsstufen für öffentliche Verkehrsmittel zur fahrtkonkreten Beeinflussung von Lichtsignalanlagen zu ermitteln und darüber hinaus Anschlüsse im öffentlichen Personennahverkehr zu sichern. Die Testergebnisse zeigen, dass die Ziele, eine höhere Pünktlichkeit und eine höhere Anschlusssicherheit, sehr gut erreicht werden.

Le transporteur est tenu d’une obligation de résultat, dont l’inexécution engage automatiquement sa responsabilité, dès lors qu’il en découle un préjudice. Mais il peut se libérer de sa responsabilité en prouvant l’existence d’une cause d’exonération. Considérée comme un obstacle à l’indemnisation, l’exonération sera appréciée avec plus ou moins de méfiance, selon le mode employé et l’objet transporté. A cet égard, il convient de distinguer le transport de passagers et le transport de marchandises. La prise en compte croissante du besoin de protection du passager fait évoluer le régime auquel est soumis le transporteur. L’analyse de cette évolution est indispensable à la recherche d’un fondement commun à la responsabilité du transporteur. Considéré comme une victime, le passager devient le pivot du régime applicable au transporteur, lequel cesse d’être un régime de responsabilité. Au contraire, lorsque la responsabilité demeure, la défense exonératoire révèle le fondement rationnel de la responsabilité du transporteur : sa faute<br>The carrier is under an obligation of result, the nonfulfilment of which he /she will be automatically held liable for, as soons as damage arises. Yet he can escape liablitiy if he can prove the existence of a ground for exemption. Considered as an impediment to compensation, the exemption will be assessed with more or less suspicion, depending on the transport mode and the cargo. In this respect, there should be a distinction made between the transport of passengers and goods. As the passenger’s need for protection is more and more taken into account, this causes the regime governing carriers to evolve. Analyzing these developments is essential to look for a common ground for the carrier’s liability. Considered as a victim, the passenger becomes the pivot of the regime applicable to the carrier, this regime being no longer a system of liablity. On the contrary, when liability remains, the defense based on exemption reveals the rationale behind the carrier’s liability: his fault

Thesis (M.Ed.) --University of Limpopo, 2006.<br>This thesis is a study on the management of learner supervision through principals’ control of punctuality in primary schools in the Mopani District. The study investigated the ways in which primary school principals manage learner supervision through control of punctuality. The investigation has brought to the light what is happening in schools regarding the management of learner supervision through control of punctuality. The literature review highlighted why learner supervision is essential in schools. Particular areas in the school and activities which require supervision were discussed. The relevance of theory to the management of learner supervision was also highlighted. The study also attempted to look at policy initiative with regard to the implementation of management of learner supervision. An attempt was made to integrate some educational policies, laws and regulations with regard to the implementation of learner supervision. The empirical research was done by the questionnaires distributed to the randomly selected schools in Mopani District and the results were discussed. The questionnaires were analysed through tables. The aim was to find out how learner supervision is managed through control of punctuality by principals from learners, educators and principals. Finally, the researcher gave general recommendations for improving the management of learner supervision through control of punctuality.

Due to a number of reasons, black commuters In South Africa are often faced with long, timeous and complicated journeys to work. The purpose of this research report is to determine how these long commuting distances influence the punctuality and rate of absenteeism of black employers to the work-place. A survey was undertaken in Cape Town, Pretoria, Bloemfontein and Durban. The sample of 1238 respondents was divided into long and short-distance commuters and the answers of these two groups were compared. Respondents were questioned about factors causing them to be late or absent from work as well as . their attitudes towards punctuality. They were also questioned about their employers' attitude towards lateness. The results showed clearly that transport related problems constituted a major part of all late arrivals at the work place. Lateness due to transport problems was mainly influenced by the distance travelled to work, the total travel time, the number of transfers, the time the commuter had to leave his home, and the time he had to start work. Although absenteeism was also increased by the distance commuters had to travel and the difficulty of the journey, it was experienced much less than lateness. Lateness at the work-place due to transport problems is a big problem in South Africa, which is aggravated by the long distances faced by many commuters. It is important to try to minimize the problem and thereby cut the cost of lateness to industry.

Dissertação de Mestrado em Engenharia e Gestão Industrial apresentada à Faculdade de Ciências e Tecnologia<br>Num mundo em constante evolução, a competitividade ressalta a importância da optimização dos sistemas. No contexto da aviação, as companhias aéreas têm como um dos factores mais visíveis a pontualidade, um aspecto de elevada importância na escolha do consumidor.Neste âmbito, o presente estudo resulta da colaboração com a companhia aérea de bandeira, a TAP - Transportes Aéreos Portugueses, SGPS, S.A., mais especificamente com a partição da equipa de Engenharia e Aeronavegabilidade da TAP Manutenção e Engenharia (TAP M&E), responsável pela frota de narrow body.Pretende-se analisar um fragmento da extensa equação de variáveis que influenciam a pontualidade enquanto factor de sucesso, a manutenção de aeronaves. Para tal, debruça-se sobre um conjunto de dados que representa uma amostra das falhas técnicas, facultado pelo Centro de Controlo de Manutenção (Maintenance Control Center, MCC) da TAP M&E. Esta amostra de dados reflecte uma seleção de ocorrências referente, apenas, à frota da TAP Air Portugal, especificamente a de narrow body.Com o objectivo de analisar a amostra e recolher dados para reajustar o planeamento das tarefas de manutenção de forma a proceder à optimização do sistema, foram identificadas incongruências na própria amostragem, as quais se tornaram objecto de investigação. Na inviabilidade de levar a cabo o objectivo primordial, a presente obra foca- se na resolução de problemas com origem no reporte das falhas técnicas, trabalhando a qualidade da base de dados correspondente. São levantadas as principais causas responsáveis por esta problemática e apresentam-se medidas correctivas, numa perspectiva de melhoria contínua.<br>In a constantly evolving world, competitiveness represents the importance of systems optimization. In aviation, airlines have punctuality as one of the most visible factors, an aspect of high importance in the customer’s choice.In this context, the present study results from the collaboration with the national airline, TAP - Transportes Aéreos Portugueses SGPS, S.A., specifically with the Engineering and Airworthiness team of TAP Maintenance and Engineering (TAP M&E) and the respective subteam that is responsible for the narrow body fleet.It is intended to analyze a fragment of the extensive equation of variables that influence punctuality as a success factor, the aircraft maintenance. Therefore, a set of data that represents a sample of technical failures is studied, provided by the Maintenance Control Center (MCC) of TAP M&E. This sample reflects a selection of occurrences referring only to TAP Air Portugal’s fleet, particularly the narrow body.In order to analyze the sample and collect data to readjust the planning of maintenance tasks so it would be possible to optimize the system, inconsistencies were identified in the sampling itself, which became a subject of investigation. Facing the impossibility of studying the primary subject, the present work focuses on solving the problems that emerge from the technical failures’s reports, while working on the actual database’s quality improvement. The main causes responsible for this problem are exposed and corrective measures are presented, in a continuous improvement’s perspective.

M. Tech. Education<br>The aim of the study is to identify the causes and challenges incurred from late coming in some selected high schools around Soshanguve with a view to providing solution to the problem within the province. Interviews were conducted with all the participants with the use of structured questionnaire and a review of document (class attendance records and late coming records book). The participants were also observed in their natural settings. Participants in the study were leaners from Grades 7 - 12, educators and principals from the selected schools.

In many languages, antipassive morphology is comprised of aspectual morphology (Polinsky 2008). This thesis presents an analysis of the syntax and semantics of antipassives in Inuktitut by exploring the link between aspectual morphology and antipassive morphology. It resolves the longstanding question as to the factors governing the distribution of the antipassive morpheme, showing that the presence of the antipassive morpheme is determined by the meaning of the construction, i.e. it does not merely change the grammatical function. It is proposed that the antipassive construction has imperfective viewpoint in contrast to the ergative construction. Antipassive morphology is obligatory with punctual telic verbs, i.e. achievements, which are verbs that have perfective viewpoint by default. Antipassive morphology is thus necessary to convey imperfective viewpoint for verbs that are by default perfective. Using a modified Reichenbachian (Reichenbach 1947) framework, it is shown that imperfective viewpoint does not allow for telic interpretations. Instead, punctuality determines the types of viewpoint, which coincide with the aspectual meaning of the antipassive marker. Viewpoint contrasts in Inuktitut are encoded not only in morphology but in changes of case and agreement configurations. They are derived using a version of the Minimalist Program (Chomsky 2008). Imperfective viewpoint can either be default, in which case there is inherent case on the internal argument, or derived through the addition of antipassive morphology, in which case the construction closely parallels a nominative-accusative structure. Perfective viewpoint is encoded through absolutive case on the internal argument, either in an ergative construction or in a canonical intransitive construction with unaccusative verbs. The thesis provides insight into the relation between case-agreement configurations and aspectual contrasts in language and the nature of those aspectual contrasts. It also provides a new approach to the relation between lexical aspect and viewpoint by considering the role of punctuality.