The aim of this work is to extrapolate the IPD Japan Capital Growth index series historically back to the early 1980’s. Using existing, long-running, macro-economic and property-related time series as inputs, we will try to set up a statistical model which can extrapolate the existing eight-year track record back for as many years as statistically significant. Our aim is to set up a model which allows us to produce a historical real estate capital growth series going back for 15 to 20 year.

In modern portfolio theory, real estate can reduce substantially the total risk in a portfolio. Therefore, a flaw in the aggregate real estate index would cause a tremendous consequence for all the stakeholders in the industry. In general, there are two major approaches in producing property indices: the appraisal-based and the transaction-based approach. The transaction-index approach is more statistical or econometric in nature, tending therefore to be more formally explicit and objective or transparent in its application procedure. Hedonic regression model is considered as the most suitable for constructing cross-sectional quality adjusted house price indices. The author thus has chosen the hedonic regression model in the empirical part as the opponent method against the Official method, the one which is adopted by the Ministry of Construction of Vietnam. The results show the Official index has a different pattern compared to the indices derived from hedonic and other models. Due to the limitation and constraints during the research period, this study does not attempt to argue for which method is more appropriate than the others, but it does provide the recommendations for the better performance of those index series in the future research.

The isssue of housing preference has been widely researched in housing literature, because it provides valuable information for the planning and development of housing for various residential groups with different needs. In Vietnam, the issue has not received proper attention from scholars and developers though the local housing market is going through a phase of rapid development and transformation. This thesis examines housing preference of young household in the capital city Hanoi with focus on condominiums in new urban areas, due to strong demand of the residential group for the specific type of housing. The thesis employed a stated-preference approach with application of direct measurement and conjoint analysis methods to answer research question. A total of 92 responses were collected by mean of questionnaires delivered to customers who visited two real-estate agents in Hanoi. Analysis of the empirical data shows that, households are most concerned about developers’ commitments and basic quality of the housing units.They appreciate child-friendly qualities of the living environment, as well as child-friendly facilities and services. The analysis also reveals that price is the most influential attribute to households’ preference, followed by location and floor area. Of the households, majority prefer living close to city centers in order to have good access to jobs, schools, health-care and recreational services; while a small portion choose to live further from city center to get better living conditions, larger space, and lower price. The preferences are then discussed in connection to current conditions of Hanoi urban areas in order to give implications for urban planning policies and new housing projects.

A decent shelter is a basic human need. In developing countries, where the industrialisation process is accompanied by rapid urbanisation, the population solves their housing situation within limits of their own savings. Therefore the majority of people in Tanzania still live in temporary, sprawling single storey dwellings which generate densification of houses and exorbitant travel distances. Occasionally settlement citizens are forced to omit job opportunities due to far and expensive transport. Not only in the informal settlements but in Dar es Salaam generally, houses with more than one storey are very rare. The horizontal development of the city may be a consequence of deficient economical resources, inappropriate regulatory framework and production techniques. Vertical extension of houses could be more economic in terms of infrastructure provision, increase spatial qualities and generate important outdoor spaces. Created space between buildings will in its turn optimises cross ventilation and results in a better indoor climate. The Swahili house is the predominant type of house found in Dar es Salaam. Its shape and layout are known by heart. Through generations, the skills of construction, has passed from one to another by practical participation. The change from rural to urban society now compels change in practice and building design. For poor families, the process of constructing a house is a complicated, prolonged and expensive procedure. Due to high cost of building materials, builders are often forced to quality compromises. This study will introduce the technique using semi ‐prefabricated construction elements as an option in affordable two storey housing. The analysis indicates that the use of these components could increase execution quality and durability of constructions. Using block elements, the prefab technique could be introduced, in a small scale, to self builders and local artisans without the need of governmental support and large industries. Presented in this thesis are drawings for a vertically extended Swahili house type which may help dwellers to build a durable and affordable two storey construction.

No description available.

Block failure is one of the most common failure modes in tunnels. Design tools have some simplifications and, therefore, they also have some model uncertainties. The purpose of this licentiate thesis is to assess the model uncertainty for different design tools in order to estimate block stability. Different approaches of kinematic limit equilibrium (KLE) including conventional KLE, limited joint length, limited joint length and stress field consideration and probabilistic KLE were compared to that of DFN-DEM. In this approach, the results of the calibrated DFN-DEM with field mapping were considered to be of true value. The results show that the conventional KLE is overdesign due to it’s over simplification. By considering fracture length and stress field, the volume of predicted unstable blocks is reduced. The probabilistic approach of KLE by considering finite joint length and stress field predicts the volume of unstable blocks to be lower than DFN-DEM approach. Therefore there is a great model uncertainty of our standard design tools for block stability analysis. The assumption made in this study is that the results from DEM were considered to have a true value; the results from analytical solution based on joint relaxation process were compared to those of DEM in a different condition of depth, K0, apical and friction angle, Kn and Ks value, and ratio of Kn/Ks. The comparison shows that for shallow depth with K0 less than 1, analytical solution leads to an overestimation of block stability. The analytical solution predicts that the block is stable, while the analyses from numerical solution show the block is unstable. The analyses show that by increasing K0, accuracy of analytical solution also increases. Moreover, for the cases with close value of friction angle to semi-apical angle, the use of analytical solution is not recommended. As the ratio of Kn/Ks increases, the accuracy of analytical solution decreases. Increasing the angle ratio (ratio between semi-apical angle to friction angle) is one source of increasing uncertainty in the model. The analytical solution is very uncertain in cases with a low value of K0, and a high value of stiffness ratio and angle ratio. On the other hand, the analytical solution is more certain in conditions with a high value of K0 and a low value of stiffness ratio and angle ratio. According to current information (K0, angle ratio, stiffness ratio), one can determine the value of model uncertainty by using the diagrams presented in Chapter 6 of the thesis. The analyses show that by having more information about the key parameters, the model uncertainty could be identified more precisely. However, having more information means spending more money, and this increase in cost must be compared to the cost of failure or delay in the project or overdesign. / Blockutfall är en av de vanligaste brottformerna i tunnlar. Dimensioneringsverktyg har förenklingar och därför har de viss modelosäkerhet. Syftet med licentiat avhandlingen är att bedöma modelosäkerhet för olika dimensioneringsverktyg för att uppskatta blockstabilitet. I Olika metoder av KLE inkluderad konventional KLE, begränsad spricklängd och insitu spänning och sannolikhetsbasserad KLE är jämförda med DFN-DEM. I den här metoden kalibreras DFN-DEM med fältkartläggning som är betraktad som sanna värden. Resultat visar att konventionell KLE ger starkt konservative resultat. Genom att betrakta spricklängden och spänningsfältet, så minskar volymen på uppskattade instabila block. Den sannolikhetsbaserade metoden för KLE genom att betrakta finit spricklängd, och spänningsfältet förutser att volymen av de instabila blocken är mindre än de som bedöms med DFN-DEM metoden. Det finns mycket osäkerhet i vår standard dimensioneringsverktyg att uppskatta block stabilitet. Antagande som gjorts i den studien är att resultatet från DEM är betraktade som sanna värden och resultaten från analytiska lösningar baserad på sprickavlastning är jämförda med resultatet från DEM. Jämförelse visar att för grunda djup och med K0 mindre än 1, den analytiska lösningen leder till en överestimering av blockstabiliteten. Den analytiska lösningen förutsäger att blocket är stabilt medan analys av den numeriska lösningen visar att blocket är instabilt. Analysen visar attgenom en ökning av K0 så ökar tillförlitligheten av den analytiska lösningen. Det visar sig att även att för fall med friktionsvinkel nära semitoppvinkeln så kan den analytiska lösningen inte rekommenderas. Vidare leder en ökning av förhållandet Kn/Ks till att tillförlitligheten av den analytiska lösningen minskar. En ökning av vinkelförhållandet mellan semitoppvinkeln och friktionsvinkeln är källa till en ökning av osäkerhet i modellen. En analytisk lösning är mer osäker i fall av lågt värde på K0 och högt värde på styvhetsförhållandet och vinkelnförhållandet. Å andra sidan, så är den analytiska lösningen mer säker i fall av högt värde på K0, och lågt värde på vinkel förhållandet och styvhetsförhållandet. Vid given information (K0, styvhetsvärde och vinkel förhållande) kan man bestämma värdet på modellosäkerheten genom att använda diagrammen i avhandlingen. Analysen visar att vid ökad information om nyckelparametrarna, så kan modelosäkerheten identifieras mer exakt. Hur som helst så betyder mer tillgång till information att mer pengar måste satsas och denna kostnad  måste gemföras med kostnader för blockinstabilitet eller överdesign.

The focus of this thesis is to study the possibility of injection grouting of embankment dams affected by internal erosion. Internal erosion is a process where certain soil material from an embankment dam is removed. This phenomenon occurs in the central core of the embankment dam. If the internal erosion is allowed to continue over a longer period of time, the dam might face a fatal situation. Since the dam core is washed out, larger voids are created, thus lowering the geotechnical stability of the dam. If the voids become larger, more seepage is allowed to pass and if more seepage passes, the internal erosion process is accelerated. The central core in an embankment dam is preferably constructed with till. Till is a natural soil that origins from the ice age. The till contains a wide range of grain sizes, basically anything from clay to blocs. The mixture of grain sizes does however give the till characteristics that are highly desirable for a water retaining construction. It is cohesive, has a low permeability, a high angle of internal friction and can be found practically anywhere in Sweden. In an embankment dam the core is the water barrier. The core alone is however weak and cannot withstand the large external forces put on a dam construction. Because of this, several zones are constructed on both sides of the core. The first zone outside the core is the filter. The filter has no cohesion and is constructed with a coarser material than the core. Outside the filter, the shell is found. The shell is constructed with even coarser material than the filter and supports the entire dam structure. Outside the shell the riprap is found. The riprap protects the dam from erosive forces such as wave erosion, ice loads and heavy rainfalls. The filters main task is to protect the core from being washed out. Since the till in the core has a wide range of grain sizes, a constant rate of seepage may start to move its finer particles (clay, silt). If the filter doesn’t catch these moving particles, a loss of material will occur. This is the basis for internal erosion. If the till has a smooth particle size distribution curve it is less prone to internal erosion. The smoothness of the curve ensures that the different grain sizes involved are evenly distributed. The finer particles are mechanically locked in place by coarser particles, which in turn are mechanically locked by even coarser grains. Finally, the soil structure is more able to withstand the erosive forces provided by the seepage. If the finer particles aren’t mechanically locked and eroded by the seepage, the filter must be designed to catch them. Therefore, internal erosion occurs only if both the till and the filter flaws. If the internal erosion is continuous, the loss of material must be replaced. By doing so without dismantling the dam, injection grouting can be performed. The grout will replace the lost core material and restore the dam. The type of grout can basically be divided into two sub groups: 1. Hardening grouts; 2. Flexible grouts.

The city of Dubai, which lies in the Middle East is, as many other cities in the area, suffering from shortage of fresh water resources. This issue is handled by desalination of sea water, which is a rather expensive procedure. Recently, the city tends to promote using hydrophobic sand in order to reduce irrigation water quantity and watering durations. Economically, this procedure has fewer costs than water desalination but concerns were raised regarding whether the chemical compounds, used in the treatment process of normal sand, impose any contamination risks for soil and groundwater. Due to the fact that normal sand has high permeability comparing to other types of soil, such as silt and clay, the rates of water seepage in normal sand is considerably high which results high water consumption in agriculture. One of the objectives of this thesis is to identify the most effective design for utilizing hydrophobic sand and normal sand layers to obtain the most suitable permeability rates for plantation purposes. Another objective is to discuss the probability of organic chemicals and heavy metals seepage when using the hydrophobic sand in soil; leaching tests were carried out to provide input to this discussion. The study showed that the hydrophobic sand has higher permeability than normal sand when it is saturated with water. However, it needs a considerably longer time in order to reach the saturation stage so recommendations were provided to use a separate layer of hydrophobic sand beneath the normal sand layer where vegetation is planted and avoid using sand mixtures. Based on the leaching tests’ results, it was also concluded that negligible concentrations of the organic silica compounds will be released into soil and ground water and the rates of heavy metals in leaching water were within the allowable limits. However, the possibility of the transformation of the organic compounds, used for normal sand treatment, into silica-free organic compounds was not discussed in this thesis. In other words, the usage of hydrophobic sand for agriculture purposes does not threaten the safety of neither soil nor groundwater concerning the leaching of the chemical compounds and metals that were tested in this study.

No description available.

No description available.