Foreword

Detta examensarbetet har utförts vid Scania AB i Södertälje. Syftet var att genom en fallstudie undersöka möjligheter till ökad produktivitet och minskade slöserier genom införandet av en ny verkstadslayout. Examensarbetet baseras dels på en litteraturstudie där ett antal leanprinciper, olika sorters produktionssystem och layoutarbete behandlas samt en empirisk studie på Scania AB. Fallstudien var uppdelad i tre faser: Kartläggning av nuläget Layoututformning Analys av den föreslagna layouten Till kartläggning av nuläget utfördes en datainsamling. Datainsamlingen bestod av både tillhandahållen sekundärdata från fallföretaget samt primärdata från egna mätningar, observationer och intervjuer för öka arbetets trovärdighet. Utifrån datainsamlingen gjordes en analys av nuläget där problemområden identifierades och dokumenterades. Analysen visade främst att Scania AB hade problem med långa ledtider och svårigheter att hålla FIFO på grund av höga PIA-nivåer. En stor anledning till de höga PIA-nivåerna gällde en organisatorisk uppdelning av produktionen i två delar med en stor mellanbuffert mellan de båda delarna. De identifierade problemområdena, cykeltider samt prognos för framtida behov användes sedan som inputparametrar vid layoutarbetet som följde Muthers (1961) metod Systematisk Layoutplanering (SLP) . Slutresultatet blev ett layoutförslag som ökade produktiviteten med ca 37% och minskade mängden slöserier på flera plan. Bland annat uppskattades ledtiden kunna sänkas från cirka 5.4 dagar till cirka 1.5 dagar och mellanbufferten helt byggas bort.This thesis has been carried out at as a single case study at Scania AB in Södertälje, Sweden. The purpose of the study was to examine possibilities to increase the productivity and eliminate waste through the implementation of a new workshop layout at Scania’s crankhaft production. The thesis was based on a literature study where different lean principles, production systems and layout shaping were covered as well as an empirical study at Scania AB. The case study was divided into four phases: Mapping of present state Layout shaping Analysis of the proposed layout A data collection was carried out before mapping the current state. The data collection consisted of both given secondary data from the case company and the primary data from own measurements, observations and interviews in order to gain credibility to the study. With the collected data an analysis of the current state was done where problem areas were identified and documented. The analysis mainly showed that Scania AB had problems with long lead times and difficulties to maintain FIFO due to high WIP-levels. A significant reason to the high WIP-levels was the result of a big inventory between the two organisational departments in the workshop. The identified problem areas, cycle times and future sale forecasts were then used as input parameters to develop a new layout using Muther’s (1968) method Systematic Layout Planning (SLP). The final result rendered in a new layout proposal which increased the productivity with 37% and eliminated waste in different areas. The lead time was estimated to decrease from the initial 5,4 days to 1,5 days with a significant decrease in the inventory mentioned above

Forecasting global growth by age structure projections

Demographic projections of age structure provide the best information available on long-term human resources and demand. In current data fairly robust correlations with GDP and GDP growth have been discovered. In this paper we use these two facts and study the forecasting properties of demographically based models. Extending the forecasts to 2050 suggests that due to fertility decreases poor countries of today will start to catch up with developed economies in which the growth process will stagnate due to the growth of the retired population.Global growth; age structure

Demography and housing demand - What can we learn from residential construction data?

There are obvious reasons why residential construction should depend on the population’s age structure. We estimate this relation on Swedish time series data and OECD panel data. Large groups of young adults are associated with higher rates of residential construction. But there is also a significant negative effect from those above 75. Age effects on residential investment are robust and forecast well out-of-sample in contrast to the corresponding house price results. This may explain why the debate around house prices and demography has been rather inconclusive. Rapidly aging populations in the industrialized world makes the future look bleak for the construction industry of these countries.demography; housing demand

Demographically based global income forecasts up to the year 2050

Demographic projections of age structure provide the best information available on long-term future human resources and demand. In current data fairly robust correlations between age structure and GDP and GDP growth have been discovered. In this paper we use these two facts and study the forecasting properties of demographically based models. Extending the forecasts to 2050 suggests that due to fertility decreases poor countries of today will start to catch up with developed economies in which the growth process will stagnate due to the growth of the elderly population. That remains the case whether or not indications of positive longevity effects are taken into account.demographic projections; global income; long-term forecasts

Age Distributions and the Current Account -A Changing Relation?

In recent research age distribution effects on the current account have been found in cross-country panel regressions. The reason is different effects on saving and investment from cohort-size variation. In a panel of annual OECD data 1960-1995, we find that the age effects on saving are similar to results on world samples but the effects on investment are very different. The respective age profiles of saving and investment are much more similar in the OECD sample. This may be one factor accounting for the home-country bias found in international capital markets. Disaggregating investment we find that young cohorts have a positive correlation with housing investment while older but still active cohorts have a positive correlation with business investment. The differences in saving and investment effects are, nevertheless, sufficient to generate persistent and sizeable age effects on the current account. Our results suggest that policies concerning current account balance should take into consideration age distributions and the degree of development.age distribution; home-country bias; saving; investment; current account; OECD

Why do People Stay? Insider Advantages and Immobility

The low mobility of people in Europe is considered a problem for adjustment to asymmetric shocks and regional convergence in the European Monetary Union. We suggest a complement to the traditional migration theories, the insider advantages approach to explain why most Europeans prefer to stay. Staying immobile they have accumulated work- and leisure-oriented insider advantages that are location-specific and would be lost in the case of emigration. Therefore, the longer people have stayed - and the more insider advantages they have accumulated -, the less likely they are to move. Using a new micro dataset covering all people resident in Sweden in 1994 and their mobility experience since 1985, we find a strong positive duration dependence of the probability to stay. Traditional micro-economic characteristics prove helpful in explaining immobility, while regional macro-economic differences have surprisingly little impact on individual mobility decisions. A large proportion of the moves between Swedish labour markets seem to be related to specific life-course events rather than to pure labour market issues. Wieso ist die Mobilität der Arbeitskräfte innerhalb der Europäischen Union - aller Freizügigkeit zum Trotz - so gering? Traditionelle Theorieansätze vermögen die schwach ausgeprägte Wanderungsintensität der EU-Angehörigen nur begrenzt zu er - klären. Denn eigentlich sollten die teilweise beträchtlichen Einkommens - und Beschäftigungsunterschiede zu weit mehr Migration innerhalb der EU führen. In diesem Diskussionspapier entwickeln wir eine Idee, die sehr wohl zu erklären vermag, weshalb für die meisten Menschen "stehen" die bessere Alternative als "gehen" ist. Der Insider-Ansatz macht deutlich, weshalb für die individuelle Entscheidung eine grenz- und kulturraumüberschreitende Wanderung die Ausnahme und nicht die Regel ist. Die empirische Überprüfung mit Hilfe eines neuen originären Mikro-Datensets, das die gesamte schwedische Wohnbevölkerung enthält, bestätigt die These, dass die Verweil- dauer einen direkten positiven Einfluss auf die Verharrenswahrscheinlichkeit ausübt. Wer lange an einem Ort lebt, wird immer wahrscheinlicher an diesem Ort bleiben!Labor and Human Capital, F22, J60, R23,

Available water supply of the Las Vegas ground-water basin Nevada

The Las Vegas ground-water basin as described in this report includes the southern part of Indian Spring Valley, Three Lakes Valley, the northern half of Ivanpah Valley, and Las Vegas Valley. These valleys in part are inferred to form a hydrologic unit that includes an area of about 3,000 square miles in the southern part of Clark County, Nev. The valleys forming the Las Vegas ground-water basin are broad structural depressions surrounded by mountains. The climate of the region is arid, and precipitation in the basin lowlands rarely exceeds 5 inches per year. Drainage is interior except for occasional Hood runoff and waste from the industrial plants at Henderson; the occasional flood runoff and waste flow through the Las Vegas Wash to Lake Mead. The mountain ranges are composed of indurated rocks that impede the movement of ground water from the basin and form the boundary of the ground-water reservoir. The valley fill that forms the principal ground-water reservoir is composed of a thick sequence ranging from Miocene (?) through Recent in age. Most of the ground water is in a large leaky artesian system comprising four principal zones of aquifers—the deep, middle, and shallow zones of artesian aquifers and the near-surface zone of water-table aquifers. To facilitate quantitative analyses of recharge, discharge, and yield, the aquifers have been divided arbitrarily into an artesian system, which includes the three principal artesian aquifers, and the near-surface water-table system. Natural recharge to the artesian system is from precipitation in the mountainswithin the drainage area of the basin. As ground water moves from areas ofrecharge toward areas of discharge in the lower parts of Las Vegas Valley, itbecomes confined between relatively impermeable beds. Nearly imperviousbarriers caused by faulting of the valley fill impede the lateral movement of the ground water. Artesian pressure causes the water to leak upward along thefaults into shallow aquifers. The average annual natural recharge to the Las Vegas artesian system was estimated by the following methods: (1) Estimation of consumptive use by phreatophytes under natural conditions prior to ground-water development; (2) estimation of ground-water underflow to the Las Vegas area during a period of near-stability in the ground-water reservoir; and (3) study of the relationship between precipitation and recharge during periods of equilibrium in the ground-water reservoir. Estimates of the natural recharge based on these methods suggest that the average annual natural recharge to the basin is on the order of 25,000 acre-feet. The total draft on the artesian aquifers in 1955 was approximately 48,000 acre-feet, of which about 42,000 acre-feet was from wells and springs and about 6,000 acre-feet was from upward leakage. Therefore, overdraft on the artesian reservoir in 1955 was about 23,000 acre-feet. Recharge to the near-surface reservoir in 1955 was derived from upward leakage from the underlying artesian aquifers and by infiltration of waste water. The total estimated recharge to the near-surface reservoir in 1955 was about 25,000 acre-feet. The draft on the near-surface reservoir in 1955 was about 25,000 acre-feet, of which about 24,000 acre-feet was discharged by phreatophytes and about 1,000 acre-feet was discharged by wells. During this study, the near-surface reservoir was in a state of approximate dynamic equilibrium.The above data indicate that the overdraft on the entire Las Vegas ground-water basin in 1955 was approximately equal to the overdraft on the artesian aquifers—that is, about 23,000 acre-feet. As the artesian heads continue to decline in Las Vegas Valley, the quantity ofground water lost through upward leakage and subsequent transpiration willdecrease. Conditions of optimum development of the artesian system will beachieved when the artesian heads have been lowered to about 50 feet below land surface, because most of the upward leakage that is currently discharged by phreatophytes will have been eliminated. At the present rate of decline of the artesian head and with the present distribution and amount of withdrawals, the artesian head will be lowered sufficiently to prevent most natural discharge in the Las Vegas area in about 40 years and in the Paradise Valley area in about 75 years. The maximum sustained yield that can be developed from the artesian aquifers when the artesian head has been lowered below the root zone of phreatophytes will be limited to the approximate average annual natural recharge to the artesian system plus the amount of nonconsumptively used ground water and imported water which becomes available for reuse through downward leakage or artificial recharge. The accumulated annual discharge from the Las Vegas artesian aquifers hasexceeded the accumulated recharge since the development of the first successful well in 1906, and as a result the artesian pressure has declined almost uninterruptedly from year to year since that time. The artesian head in selected observation wells in the vicinity of Las Vegas and Paradise Valley declined about 30 feet between 1941 and 1956. During this time the approximate cumulative overdraft amounted to about 300,000 acre-feet. The amount of overdraft per foot of lowering of artesian head within the area of approximately 40 square miles represented by the observation wells during this period was about 10,000 acre-feet.The chemical quality of the ground water in Las Vegas Valley is, in general,better in the northern than in the southern part of the valley. In the northernpart of the valley, water from the shallow and middle zones of aquifers is of better quality than water in the deep zone of aquifers. As the ground water migrates southward into the Paradise Valley and the Whitney-Pittman areas, the water in the middle and shallow zones becomes more mineralized than the water in the deep zone of aquifers. The lowering of artesian head in the Las Vegas area between 1935 and 1950has caused about 180 millimeters of local land subsidence in the vicinity of the Bonanza Street underpass, where the sediments are predominantly clay and silt. In the western part of the valley, where the sediments are predominantly sand and gravel, subsidence during the same period of time was negligible

Breathing exercises for dysfunctional breathing/hyperventilation syndrome in adults

Copyright © 2013 The Cochrane Collaboration. Published by JohnWiley & Sons, Ltd.Background: Dysfunctional breathing/hyperventilation syndrome (DB/HVS) is a respiratory disorder, psychologically or physiologically based, involving breathing too deeply and/or too rapidly (hyperventilation) or erratic breathing interspersed with breath-holding or sighing (DB). DB/HVS can result in significant patient morbidity and an array of symptoms including breathlessness, chest tightness, dizziness, tremor and paraesthesia.DB/HVS has an estimated prevalence of 9.5%in the general adult population, however, there is little consensus regarding the most effective management of this patient group. Objectives: 1) To determine whether breathing exercises in patients with DB/HVS have beneficial effects as measured by quality of life indices. 2) To determine whether there are any adverse effects of breathing exercises in patients with DB/HVS Search methods: We identified trials for consideration using both electronic and manual search strategies. We searched CENTRAL, MEDLINE, EMBASE, and four other databases. The latest search was in February 2013. Selection criteria: We planned to include randomised, quasi-randomised or cluster randomised controlled trials (RCTs) in which breathing exercises, or a combined intervention including breathing exercises as a key component, were compared with either no treatment or another therapy that did not include breathing exercises in patients with DB/HVS. Observational studies, case studies and studies utilising a cross-over design were not eligible for inclusion. We considered any type of breathing exercise for inclusion in this review, such as breathing control, diaphragmatic breathing, yoga breathing, Buteyko breathing, biofeedback-guided breathingmodification, yawn/sigh suppression. Programs where exercises were either supervised or unsupervised were eligible as were relaxation techniques and acute-episode management, as long as it was clear that breathing exercises were a key component of the intervention. We excluded any intervention without breathing exercises or where breathing exercises were not key to the intervention

Calibrating Control-Bounded ADCs

The paper considers the calibration of control-bounded analog-to-digital converters. It is demonstrated that variations of the analog frontend can be addressed by calibrating the digital estimation filter. In simulations (both behavioral and transistor level) of a leapfrog analog frontend, the proposed calibration method restores essentially the nominal performance. Moreover, with digital-filter calibration in mind, the paper reformulates the design problem of control-bounded converters and thereby clarifies the role of sampling, desired filter shape, and nominal conversion error.Comment: 5 pages, 5 figures, submitted to ISCAS 202

Continuum Coupling and Single-Nucleon Overlap Integrals

The presence of a particle continuum, both of a resonant and non-resonant character, can significantly impact spectroscopic properties of weakly bound nuclei and excited nuclear states close to, and above, the particle emission threshold. In the framework of the continuum shell model in the complex momentum-plane, the so-called Gamow Shell Model, we discuss salient effects of the continuum coupling on the one-neutron overlap integrals and the associated spectroscopic factors in neutron-rich helium and oxygen nuclei. In particular, we demonstrate a characteristic near-threshold energy dependence of the spectroscopic factors for different l-waves. We show also that the realistic radial overlap functions, which are needed for the description of transfer reactions, can be generated by single-particle wave functions of the appropriately chosen complex potential.Comment: 9 figures; 23 pages; corrected version; accepted in Nuclear Physics