The fact that traffic congestion upstream of a bottleneck causes a reduction in the discharge flow rate through the bottleneck has been well documented in several empirical studies. However, what has been missing is an understanding of the causes of these empirically observed flow reductions. An identification of these causes is important in order to develop various mitigation schemes through the use of emerging technology. The concept of capacity drop can be introduced at time-independent bottlenecks (e.g. freeways) as well as time-dependent bottlenecks (e.g. signalized intersections). While to the author's knowledge no one has attempted to link these phenomena, the research presented in this thesis serves as a first step in doing so. The research uses the INTEGRATION simulation software, after demonstrating its validity against empirical data, to simulate time-independent and time-dependent bottlenecks in an attempt to characterize and understand the contributing factors to these flow reductions. Initially, the INTEGRATION simulation software is validated by comparing its results to empirically observed traffic stream behavior. This thesis demonstrates that the discharge flow rate is reduced at stationary bottlenecks at the onset of congestion. These reductions at stationary bottlenecks are not recovered as the traffic stream propagates downstream. Furthermore, these reductions are not impacted by the level of vehicle acceleration. Alternatively, the drop in the discharge flow rate caused by time-dependent bottleneck is recoverable and is dependent on the level of acceleration. The difference in behavior is attributed to the fact that in the case of a stationary bottleneck the delay in vehicle headways exceeds the losses caused by vehicle accelerations and thus is not recoverable. In the case of vehicles discharging from a backward recovery wave the dominant factor is the delay caused by vehicle acceleration and this can be recuperated as the traffic stream travels downstream. / Master of Science

<p>A considerable amount of research has concentrated on the modes of transportation. Research has tended to focus on the growth and trends of the different modes of transportation on the national scale. Very little research has been undertaken into each region, and even less on those factors that prevent or act as barriers for transportation of goods in each region. Furthermore, very little research has been undertaken that examines the bottlenecks of the transportation flows in Jönköping.</p><p>By interviewing the main actors in the region, this thesis identifies the main product flow in the Jönköping County. The study also examines the perceived bottlenecks to transportation of goods that logistics companies face. In conducting the study, the main impediments to transportation flows were identified, analysed and ranked. The findings indicate that there are many common bottlenecks between firms in Jönköping. The study also, to an extent, supports findings that have been made in studies carried out previously by other researchers.<strong></strong></p>

Severe population bottlenecks and the small size of many remnant habitats may render many bird populations prone to extinction from disease outbreaks. Bottlenecks may increase inbreeding which in turn may result in a low diversity of resistance and an immune system that is impaired or defective. Thus, bottlenecked populations may be less immunocompetent and more vulnerable to microbiological and parasitic perturbations. Few studies have assessed the effect of bottlenecks on the immunocompetence of birds. In this study, I used twelve saddleback (Philesturnus carunculatus) and two New Zealand robin (Petroica a. australis) populations, to determine if the severe bottlenecks reduce the immunocompetence of birds. When I experimentally challenged the immune system of two robin populations I found that despite the two populations having similar parasite loads, robins from the severely bottlenecked Motuara Island population exhibited a significantly lower T-cell mediated immune response than the source population (Nukuwaiata Island) suggesting that birds passing through severe population bottlenecks have a compromised immunocompetence. In the saddleback, severe bottlenecks, as well as high population densities and small island size, lead to individuals exhibiting higher stress levels and feather mite loads and lower immune function, as was evident by lower lymphocyte counts. I did not find levels of fluctuating asymmetry of saddlebacks to be directly influenced by bottleneck size. However, I did find that individuals with higher levels of fluctuating asymmetry had higher loads of hippoboscid flies and lower loads of coccidia suggesting a possible trade-off between growth and immune function. In contrast to previous studies looking at behavioural secondary sexual traits, I found no effect of founder number on the size of wattles in saddleback. I did however demonstrate that wattle size reflected the level of immune function in females as well as males, suggesting that females play a far greater role in offspring fitness than has been appreciated in traditional theories of sexual selection. Overall, my results indicate that severe bottlenecks can lead to reductions in immunocompetence in the resulting populations, especially in those populations that pass through the most severe bottlenecks. Based on the evidence from my thesis, I recommend conservation managers should aim to use at least 90 individuals to found new populations in order to reduce the deleterious effects of bottlenecks on immune function. If the costs of population bottlenecks and inbreeding are to be avoided, conservationists must adequately address the role of genetic factors in susceptibility to disease, and work towards minimising the risk of severe population bottlenecks in the management of endangered birds

A soja é a commodity brasileira que mais influencia positivamente a balança comercial do Brasil, que apresenta vantagens competitivas neste mercado como tecnologia de produção, amplas áreas produtivas e clima propício para o cultivo. Porém, um gargalo significativo para a expansão da cultura da soja no Brasil, é sua atual condição logística. O estado do Mato Grosso que lidera a produção nacional de soja, é exemplo importante destes problemas logísticos, tanto no transporte, quanto na estrutura de armazenagem. Assim, o objetivo principal deste trabalho é o de analisar os gargalos logísticos das principais rotas de escoamento de grãos de soja do Estado do Mato Grosso. O trabalho baseia-se em pesquisa exploratória qualitativa utilizando-se de estudo de caso por meio de entrevistas semiestruturadas. O estudo de caso sobre o complexo portuário Miritituba-Barcarena no Pará evidenciou que esta nova rota é uma saída logística encontrada pelo setor privado para driblar os problemas logísticos do estado do Mato Grosso, utilizando-se do modal hidroviário como principal meio de transporte. Este diferencial logístico é corroborado pelos resultados das entrevistas semiestruturadas realizadas, o que leva à conclusão de que o modal rodoviário não deve ser o único e exclusivo meio de escoamento da soja em grão no estado do Mato Grosso, seja por suas condições impróprias ou por não ser a forma otimizada de transporte de commodities. Por fim, destaca-se que este caso além de ser uma opção viável que contribui para que a produção de soja do Mato Grosso possa ser escoada e exportada, deve ser encarado como exemplo de prática a ser adotada por gestores de empresas e para estudos e iniciativas futuras. / Soy is the Brazilian commodity that most positively influences Brazil\'s trade balance, which has competitive advantages in this market such as production technology, large production areas and climate favorable for cultivation. However, a significant bottleneck for soybean expansion in Brazil is its current logistics condition. The state of Mato Grosso, which leads the national soybean production, is an important example of these logistical problems, both in transport and in storage structure. Thus, the main objective of this study is to analyze the logistical bottlenecks of the main routes of flow of Mato Grosso State soybean. The work is based on qualitative exploratory research using case study through semi-structured interviews. The case study of the port complex Miritituba-Barcarena in Pará showed that this new route is a logistics solution found by the private sector to circumvent the logistical problems of the state of Mato Grosso, using the water transport as the main means of transportation. This logistics differential is corroborated by the results of semi-structured interviews, which leads to the conclusion that the road transport should not be the sole and exclusive mean of soybean flow in Mato Grosso, either by their improper condition or for not being the optimal commodity way of transportation. Finally, it is emphasized that this case, in addition to being a viable option that contributes to the production of soy in Mato Grosso being flowed and exported, it should be seen as an example to be adopted by company managers, for studies and future initiatives.

A considerable amount of research has concentrated on the modes of transportation. Research has tended to focus on the growth and trends of the different modes of transportation on the national scale. Very little research has been undertaken into each region, and even less on those factors that prevent or act as barriers for transportation of goods in each region. Furthermore, very little research has been undertaken that examines the bottlenecks of the transportation flows in Jönköping. By interviewing the main actors in the region, this thesis identifies the main product flow in the Jönköping County. The study also examines the perceived bottlenecks to transportation of goods that logistics companies face. In conducting the study, the main impediments to transportation flows were identified, analysed and ranked. The findings indicate that there are many common bottlenecks between firms in Jönköping. The study also, to an extent, supports findings that have been made in studies carried out previously by other researchers.

Bakgrund: Ett lager är en viktig del av de flesta värdekedjor. Stora ansträngningar har därför under de senaste åren gjorts för att finna optimala strategier för planering och kontroll av lagersystem. För att uppnå en ökad produktion krävs det att kapacitetsutnyttjandet förbättras. Genom att planera sin kapacitet kan företag reducera kapacitetsbegräsningar, så kallade flaskhalsar, som är nyckeln till att förbättra produktionens kapacitetsutnyttjande. Syfte: Syftet med studien är att beskriva Staples nuvarande kapacitetsutnyttjande i påfyllnads- och plockprocessen. Vidare avser studien att identifiera kapacitetsbegränsningar inom dessa processer. Därefter ämnar studien att finna de bakomliggande orsakerna till dessa kapacitetsbegränsningar samt hur de kan förbättras. Metod: Det har genomförts ostrukturerade intervjuer, semi-strukturerade intervjuer, deltagande observationer samt insamling av kvantitativ data. Inledningsvis genomfördes en processkartläggning i syfte som ett verktyg för resterande delar av studien. Vidare utfördes beräkningar för att finna flaskhalsar i produktionen och intervjuer för att identifiera störningsmoment inom flaskhalsarna. Slutligen presenterades ett antal förbättringsförslag. Slutsatser: Efter genomförda beräkningar framgick att Staples idag inte utnyttjar sin kapacitet maximalt, dock är maximal kapacitet är en nivå som inte anses vara rimlig. Det framgick att Staples har ett kapacitetsbortfall på grund av att det finns en differens mellan nominell kapacitet och bruttokapacitet. Slutsatsen drogs att följande tre aktiviteter utgör flaskhalsar i Staples verksamhet; godsmottagning, plock ZtZ (plock av framförallt tyngre och otympliga artiklar) och plock PTS (detaljplock). Inom dessa flaskhalsar påträffades ett antal störningsmoment som till stor del har grund inom deiiiteoretiska områdena som Stevenson (2009), Slack et al. (2012) och Bergman och Klefsjö (2012) benämner som anläggning och teknik samt metod. Vidare fastslogs att en svårighet finns i att ge kortsiktiga förbättringsförslag för dessa störningsmoment. Detta på grund av studiens tidsram samt att det berör ämnen utanför studiens omfattning. Det presenteras dock tre scenarier för att hitta en fördelaktig fördelning av kapacitet mellan PTS och ZtZ. Dessa scenarier bygger på tre tidsintervaller för hur produktionen är igång samt två plockhastigheter. Baserat på att PTS:en innehar en större andel aktiva arbetstimmar och en högre plockhastighet är scenario 3 mest fördelaktigt eftersom det krävs att ZtZ är minst verksam. / Background: A warehouse is an important part of most value chains. Great effort has in recent years been made to find optimal strategies for planning and control of storage system. In order to achieve a higher production it requires the capacity utilization to be improved. By planning its capacity, companies can reduce capacity constraints, so-called bottlenecks, which is the key to improving the production’s capacity utilization. Purpose: The aim of this study is to describe Staples current capacity utilization in the filling and picking process. Furthermore, the study aim to identify capacity constraints in these processes. Then, the study intends to find the causes of these capacity constraints and how they can be improved. Method: There have been unstructured interviews, semi-structured interviews, participant observation and collection of quantitative data. Initially there was a process mapping in purpose of a tool for the remaining study. Further calculations were performed to find bottlenecks in the production and interviews to identify disturbances in the bottlenecks. Finally, a number of suggestions for improvement where presented. Conclusions: Calculations revealed that Staples is currently not using their capacity to the maximum, altough this is not a level considered reasonable. It appeared that the company has a capacity shortfall when there was a difference between the nominal capacity and gross capacity. It was concluded that the following three activities constituted bottlenecks in Staples; receiving, picking ZtZ (picking of particularly heavy and bulky items) and picking PTS (detail picking). Within these bottlenecks, there was a number of disturbances found that largely had their basis in the teoratical areas Stevenson (2009), Slack et al. (2012) and Bergman and Klefsjö (2012) terms as facility and technology and method. Furthermore, it was established a difficulty in providingvshort-term improvement suggestions to these disturbances. This’s because of the study's time frame and that it reach subjects outside the scope of the study. However, three scenarios are presented to find a favorable allocation of capacity between PTS and ZTZ. These scenarios are based on three time intervals for how production is running and two picking speeds. Based on that the PTS holds a higher proportion of active working hours and a faster pick-speed scenario 3 is the most beneficial because it requires that ZTZ is least active.

Severe population bottlenecks and the small size of many remnant habitats may render many bird populations prone to extinction from disease outbreaks. Bottlenecks may increase inbreeding which in turn may result in a low diversity of resistance and an immune system that is impaired or defective. Thus, bottlenecked populations may be less immunocompetent and more vulnerable to microbiological and parasitic perturbations. Few studies have assessed the effect of bottlenecks on the immunocompetence of birds. In this study, I used twelve saddleback (Philesturnus carunculatus) and two New Zealand robin (Petroica a. australis) populations, to determine if the severe bottlenecks reduce the immunocompetence of birds. When I experimentally challenged the immune system of two robin populations I found that despite the two populations having similar parasite loads, robins from the severely bottlenecked Motuara Island population exhibited a significantly lower T-cell mediated immune response than the source population (Nukuwaiata Island) suggesting that birds passing through severe population bottlenecks have a compromised immunocompetence. In the saddleback, severe bottlenecks, as well as high population densities and small island size, lead to individuals exhibiting higher stress levels and feather mite loads and lower immune function, as was evident by lower lymphocyte counts. I did not find levels of fluctuating asymmetry of saddlebacks to be directly influenced by bottleneck size. However, I did find that individuals with higher levels of fluctuating asymmetry had higher loads of hippoboscid flies and lower loads of coccidia suggesting a possible trade-off between growth and immune function. In contrast to previous studies looking at behavioural secondary sexual traits, I found no effect of founder number on the size of wattles in saddleback. I did however demonstrate that wattle size reflected the level of immune function in females as well as males, suggesting that females play a far greater role in offspring fitness than has been appreciated in traditional theories of sexual selection. Overall, my results indicate that severe bottlenecks can lead to reductions in immunocompetence in the resulting populations, especially in those populations that pass through the most severe bottlenecks. Based on the evidence from my thesis, I recommend conservation managers should aim to use at least 90 individuals to found new populations in order to reduce the deleterious effects of bottlenecks on immune function. If the costs of population bottlenecks and inbreeding are to be avoided, conservationists must adequately address the role of genetic factors in susceptibility to disease, and work towards minimising the risk of severe population bottlenecks in the management of endangered birds

Thesis (Ph.D.)--University of California, Berkeley, 2010. / "Spring 2010." Includes bibliographical references (p. 35-36).

A soja é a commodity brasileira que mais influencia positivamente a balança comercial do Brasil, que apresenta vantagens competitivas neste mercado como tecnologia de produção, amplas áreas produtivas e clima propício para o cultivo. Porém, um gargalo significativo para a expansão da cultura da soja no Brasil, é sua atual condição logística. O estado do Mato Grosso que lidera a produção nacional de soja, é exemplo importante destes problemas logísticos, tanto no transporte, quanto na estrutura de armazenagem. Assim, o objetivo principal deste trabalho é o de analisar os gargalos logísticos das principais rotas de escoamento de grãos de soja do Estado do Mato Grosso. O trabalho baseia-se em pesquisa exploratória qualitativa utilizando-se de estudo de caso por meio de entrevistas semiestruturadas. O estudo de caso sobre o complexo portuário Miritituba-Barcarena no Pará evidenciou que esta nova rota é uma saída logística encontrada pelo setor privado para driblar os problemas logísticos do estado do Mato Grosso, utilizando-se do modal hidroviário como principal meio de transporte. Este diferencial logístico é corroborado pelos resultados das entrevistas semiestruturadas realizadas, o que leva à conclusão de que o modal rodoviário não deve ser o único e exclusivo meio de escoamento da soja em grão no estado do Mato Grosso, seja por suas condições impróprias ou por não ser a forma otimizada de transporte de commodities. Por fim, destaca-se que este caso além de ser uma opção viável que contribui para que a produção de soja do Mato Grosso possa ser escoada e exportada, deve ser encarado como exemplo de prática a ser adotada por gestores de empresas e para estudos e iniciativas futuras. / Soy is the Brazilian commodity that most positively influences Brazil\'s trade balance, which has competitive advantages in this market such as production technology, large production areas and climate favorable for cultivation. However, a significant bottleneck for soybean expansion in Brazil is its current logistics condition. The state of Mato Grosso, which leads the national soybean production, is an important example of these logistical problems, both in transport and in storage structure. Thus, the main objective of this study is to analyze the logistical bottlenecks of the main routes of flow of Mato Grosso State soybean. The work is based on qualitative exploratory research using case study through semi-structured interviews. The case study of the port complex Miritituba-Barcarena in Pará showed that this new route is a logistics solution found by the private sector to circumvent the logistical problems of the state of Mato Grosso, using the water transport as the main means of transportation. This logistics differential is corroborated by the results of semi-structured interviews, which leads to the conclusion that the road transport should not be the sole and exclusive mean of soybean flow in Mato Grosso, either by their improper condition or for not being the optimal commodity way of transportation. Finally, it is emphasized that this case, in addition to being a viable option that contributes to the production of soy in Mato Grosso being flowed and exported, it should be seen as an example to be adopted by company managers, for studies and future initiatives.

Dagens företag blir allt mer resursbejakande. Ett sätt att bli mer effektiva med resurser är lean production, en strategisk metod som går ut på att eliminera slöseri. Värdeflödesanalys är ett verktyg inom lean som kan användas för att få en klarare bild av hur verkligheten ser ut och hjälpa till att få en klarare bild av vart problemen ligger. När en sådan analys har gjorts upptäcks ofta en maskin eller station som saktar ner produktionen. Sådana stationer kallas ”flaskhalsar”. Syftet med denna studie är att utforma en metodik för analys och effektivisering av materialflöden baserat på flaskhalsteori och lean production. Metodiken testas på Företag AB:s filial. Utifrån litteraturstudier arbetades metodiken fram, den består i huvudsak av två steg, nulägesbeskrivning och analyserande diskussion. Dessa steg sker med stöd av olika faktorer inom lean production och flaskhalsteori. Metodiken tillämpades på vårat fallföretag, och visade sig bl.a. vara ett strukturerat sätt för att studera nuläet och diskutera förbättringsförslag. Litteraturstudier har genomförts för insamling av teori. På företaget genomfördes intervjuer och observationer med personal och chefer som var delaktiga i flödet som studerades, SK23DF. Filialen på Företag AB jobbar med 150 olika stålsorter och ca 3000 olika produkter. Flödet är dessutom korsande och prognosstyrt och det medför att det blir ett massivt undertagande att effektivisera dessa på bästa sätt. Slutsatser som nåtts är att personalens nuvarande samsyn för effektiv produktion är ett hinder för detta. Personalen bör utbildas för att få en större bild av helheten och på så sätt ge dem bättre förutsättningar vid förändring och förbättringsarbete. All forskning pekar på att en god förståelse av nuläget, av samtliga inom organisationen, är nyckeln till ett lyckat förändringsarbete vid effektivisering av flöden. / Companies today are becoming more and more resource-promoting. A way for companies to become more effective with their resources is Lean Production, which is a strategic method that involves eliminating waste. Value stream mapping is a tool that can be used to get a clearer picture of reality and visualize where the problem lies. When the analysis is done, it will often show a machine or station that is slowing down production. Stations like that are called ”bottlenecks”. The purpose with this study is to form a methodology for analysis and efficiency of material flows based on bottleneck theory and lean production. The methodology will be tested on Företag AB:s filial. The methodology was worked out from literature studies. It consists of two main steps, status report and analyzing discussion. These two steps is supported by different factors within lean production and bottleneck theory. The methodology is applied on our business case and showed to be a structured way to study the current state of production and to discuss improvements. Literature studies has been used to gather theoretical knowledge. Within the company interviews and observations were conducted with operators and executives who was involved with the product flow that was investigated, SK23DF. Företag AB:s filial works with 150 different types of steel with about 3000 different products. The production flow is also forecast-controlled and intersecting and it is a massive under-taking to streamline these in the best way possible. Conclusions reached is that the staff's current consensus for efficient production is an obstacle to this. The staff should be trained to get a bigger picture of the whole, thus giving them better prospects for change and improvement. All research points to the importance of fully understanding the current situation, by everyone within the organization. This is the key to succeed with change management at streamlining flows.