Real options and game theoretical approaches to real estate development projects: multiple equilibria and the implications of different tie-breaking rules

This paper contributes to a fast growing literature which introduces game theory in the analysis of real option investments in a competitive setting. Specifically, in this paper we focus on the issue of multiple equilibria and on the implications that different equilibrium selections may have for the pricing of real options and for subsequent strategic decisions. We present some theoretical results of the necessary conditions to have multiple equilibria and we show under which conditions different tie-breaking rules result in different economic decisions. We then present a numerical exercise using the in formation set obtained on a real estate development in South London. We find that risk aversion reduces option value and this reduction decreases marginally as negative externalities decrease.

Rescuing a telecom giant from the jaws of bankruptcy: a case study and an interview with Sir Richard Lapthorne, chairman of Cable & Wireless

Purpose – The purpose of this paper is to demonstrate key strategic decisions involved in turning around a large multinational operating in a dynamic market. Design/methodology/approach – The paper is based on analysis of archival documents and a semi-structured interview with the chairman of the company credited with its rescue. Findings – Turnaround is complex and involves both planned and emergent strategies. The progress is non-linear requiring adjustment and change in direction of travel. Top management credibility and vision is critical to success. Rescue is only possible if the company has a strong cash generative business among its businesses. The speed of decision making, decisiveness and the ability to implement strategy are among the key ingredients of success. Originality/value – Turnaround is an under-researched area in strategy. This paper contributes to a better understanding in this important area and bridges the gap between theory and practice. It provides a practical view and demonstrates how a leading executive with significant expertise and successful turnaround track record deals with inherent dilemmas of turnaround

Optimization of cable cycles : a trade-off between reliability and cost

This paper elaborates the routing of cable cycle through available routes in a building in order to link a set of devices, in a most reasonable way. Despite of the similarities to other NP-hard routing problems, the only goal is not only to minimize the cost (length of the cycle) but also to increase the reliability of the path (in case of a cable cut) which is assessed by a risk factor. Since there is often a trade-off between the risk and length factors, a criterion for ranking candidates and deciding the most reasonable solution is defined. A set of techniques is proposed to perform an efficient and exact search among candidates. A novel graph is introduced to reduce the search-space, and navigate the search toward feasible and desirable solutions. Moreover, admissible heuristic length estimation helps to early detection of partial cycles which lead to unreasonable solutions. The results show that the method provides solutions which are both technically and financially reasonable. Furthermore, it is proved that the proposed techniques are very efficient in reducing the computational time of the search to a reasonable amount.

Polipropileno graftizado com metacrilato glicidila como agente compatibilizante em blendas de PP e nylon 6

Neste trabalho foi feito uma avaliação do polipropileno funcionalizado com metacrilato de glicidila (PP-GMA) como agente compatibilizante em blendas reativas de polipropileno e nylon 6. As reações de funcionalização do polipropileno (PP) com metacrilato de glicidila (GMA) foram feitas em estado fundido e os polímeros modificados (PP-GMA) foram utilizados em misturas de PP com nylon 6, para a avaliação das propriedades mecânicas, térmicas e morfológicas da blenda. As blendas foram preparadas variando a concentração de nylon 6 e também do agente compatibilizante. Após o estudo da ação da concentração de nylon 6 e do agente compatibilizante nas blendas, foi verificado o comportamento do PP-GMA com diferentes teores de incorporação molar do GMA no polipropileno. Utilizou-se dois tipos de nylon 6, um deles com maior número de terminais carboxílicos, a fim de avaliar o efeito desses grupos na compatibilidade do sistema. As blendas obtidas foram caracterizadas por calorimetria diferencial de varredura, microscopia eletrônica de varredura e análise das propriedades mecânicas e dinâmico-mecânicas. Os resultados mostraram que a adição do PP-GMA provoca alterações na morfologia das blendas, apresentando uma melhor dispersão e redução no tamanho das partículas dispersas. Além disso, há um aumento nas propriedades mecânicas comparado com as propriedades das blendas não compatibilizadas, que pode ser atribuído a melhor adesão entre as fases para ambos os nylons utilizados neste trabalho. Foi feito estudo comparativo entre as blendas de PP/PP-GMA/Ny6 e PP/PP-MA/Ny6 na proporção de 63/7/30. O efeito do tipo de agente compatibilizante foi caracterizado por calorimetria diferencial de varredura, microscopia eletrônica de varredura e análise das propriedades mecânicas e dinâmico-mecânicas. Os resultados indicaram que o polipropileno modificado com anidrido maleico (PP-MA) mostrou um melhor efeito compatibilizante nesses sistemas. Ou seja, a interação dos terminais amino do nylon foram mais suscetíveis a ação do grupamento anidrido no PP-MA, do que o grupamento epóxido no PP-GMA.

A feasibility study for modelling tie strength with the facebook API

This thesis examines the concept of tie strength and investigates how it can be determined on the fly in the Facebook Social Network Service (SNS) by a system constructed using the standard developer API. We analyze and compare two different models: the first one is an adaptation of previous literature (Gilbert & Karahalios, 2009), the second model is built from scratch and based on a dataset obtained from an online survey. This survey took the form of a Facebook application that collected subjective ratings of the strength of 1642 ties (friendships) from 85 different participants. The new tie strength model was built based on this dataset by using a multiple regression method. We saw that the new model performed slightly better than the original adapted model, plus it had the advantage of being easier to implement. In conclusion, this thesis has shown that tie strength models capable of serving as useful friendship predictors are easily implementable in a Facebook application via standard API calls. In addition to a new tie strength model, the methodology adopted in this work permitted observation of the weights of each predictive variable used in the model, increasing the visibility of the factors that affects peoples’ relationships in online social networks.

The strut-and-tie models in reinforced concrete structures analysed by a numerical technique

Os modelos de bielas e tirantes são procedimentos de análise apropriados para projetar elementos de concreto armado em casos de regiões onde há alterações geométricas ou concentrações de tensões, denominadas regiões D. Trata-se de bons modelos de representação da estrutura para avaliar melhor o seu comportamento estrutural e seu mecanismo resistente. O presente artigo aplica a técnica da otimização topológica para identificar o fluxo de tensões nas estruturas, definindo a configuração dos membros de bielas e tirantes, e quantifica seus valores para dimensionamento. Utilizam-se o método ESO, e uma variante desse, o SESO (Smoothing ESO) com o método dos elementos finitos em elasticidade plana. A filosofia do SESO baseia-se na observação de que se o elemento não for necessário à estrutura, sua contribuição de rigidez vai diminuindo progressivamente. Isto é, sua remoção é atenuada nos valores da matriz constitutiva, como se este estivesse em processo de danificação. Para validar a presente formulação, apresentam-se alguns exemplos numéricos onde se comparam suas respostas com as advindas de trabalhos científicos pioneiros sobre o assunto.

Testicular biopsy with Tru-Cut needle in conjunction with fibrin adhesive or nylon suture: assessment of post-biopsy testicular function in rams

Testicular biopsy has been a complementary technique for clinical and research purposes to evaluate reproductive function in males. However, hemorrhage, inflammation, degeneration, and adhesion are factors that might limit the use of this procedure. In order to minimize these potential problems, fibrin glue derived from snake venom, a tissue adhesive with sealing, hemostatic, and healing properties, was used in conjunction with bilateral testicular biopsy with the Tru-Cut needle and was compared with a more conventional technique that uses nylon suture. Thirty mature rams were randomly assigned to three groups of 10 animals each, as follows: nonsurgical control group (no scrotal surgery, or biopsy); biopsy + glue group (fibrin glue on puncture sites and skin incisions) and biopsy + suture group (compression with swab on puncture sites and suturing of skin incision). The surgeries of the rams in the biopsy groups were performed on the same day, which was designated Day 0 for all three groups. Data of scrotal circumference, number of spermatozoa per ejaculum, percentage of morphologically abnormal spermatozoa, spermatozoa motility, and serum testosterone concentrations from Days -7, 20, 40, 60, 80 and 100 were evaluated. There were no significant differences between groups within days for any of the parameters evaluated. In conclusion, the testicular biopsy procedure using the Tru-Cut needle in conjunction with conventional nylon suture or the more novel fibrin glue in rams did not affect any of the parameters of testicular function evaluated in this study and was shown to be relatively simple, safe and efficient. (C) 2002 Published by Elsevier B.V. B.V.

Acrylonitrile-butadiene-styrene toughened nylon 6: The influences of compatibilizer on morphology and impact properties

Polymer alloys have been used as an alternative to obtain polymeric materials with unique physical properties. Generally, the polymer mixture is incompatible, which makes it necessary to use a compatibilizer to improve the interracial adhesion. Nylon 6 (PA6) is an attractive polymer to use in engineering applications, but it has processing instability and relatively low notched impact strength. In this study, the acrylonitrile-butadiene-styrene (ABS) triblock copolymer was used as an impact modifier for PA6. Poly(methyl methacrylate-co-maleic anyhydride) (MMA-MA) and poly(methyl methacrylate-co-maleic methacrylate) (MMA-GMA) were used as compatibilizers for this blend. The morphology and impact strength of the blends were evaluated as a function of blend composition and the presence of compatibilizers. The blends compatibilized with maleated copolymer exhibited an impact strength up to 800 J/m and a morphology with ABS domains more efi8ciently dispersed. Moderate amounts of MA functionality in the compatibilizer (∼5%) and small amounts of compatibilizer in the blend (∼5%) appear sufficient to improve the impact properties and ABS dispersion. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87.

Morphological, mechanical and rheological properties of nylon 6/acrylonitrile-butadiene-styrene blends compatibilized with MMA/MA copolymers

The morphological, mechanical and rheological properties of nylon 6/acrylonitrile-butadiene-styrene blends compatibilized with MMA-MA [poly(methyl methacrylate-comaleic anhydride)] copolymers were studied. A twin screw extruder was used for melt-blended the polymers and the injection moulding process was used to mold the samples. The main focus was on nylon 6/ ABS blends compatibilized with one MMA-MA copolymer. This copolymer has PMMA segments that appear to be miscible with the styrene-acrylonitrile (SAN) phase of ABS and the anhydride groups can react with amine end groups of the nylon 6 (Ny6) to form graft copolymers at the interface between Ny6 and ABS rich phases. Tensile and impact and morphological properties were enhanced by the incorporation of this copolymer. Transmission electron microscopy (TEM) observations revealed that the ABS domains are finely dispersed in nylon 6 matrix and led to the lowest ductile-brittle transition temperatures and highest impact properties. It can be concluded that the MMA-MA copolymer is an efficient alternative for the reactive compatibilization and can be used as a compatibilizer for nylon 6/ABS blends.© 2003 Kluwer Academic Publishers.

Morphology of Nylon 6/Acrylonitrile-Butadiene-Styrene Blends Compatibilized by a Methyl Methacrylate/Maleic Anhydride Copolymer

The morphologies of nylon 6/acrylonitrile-butadiene-styrene blends compatibilized with a methyl methacrylate/maleic anhydride copolymer, with 3-20 wt % maleic anhydride, were examined by transmission electron microscopy. Some staining techniques were employed for identifying the various phases. The binary blends were immiscible and exhibited poor mechanical properties that stemmed from the unfavorable interactions among their molecular segments. This produced an unstable and coarse phase morphology and weak interfaces among the phases in the solid state. The presence of the copolymer in the blends clearly led to a more efficient dispersion of the acrylonitrile-butadiene-styrene phase and consequently optimized Izod impact properties. © 2003 Wiley Periodicals, Inc.

Effect of compatibilizer in acrylonitrile-butadiene-styrene toughened nylon 6 blends: Ductile-brittle transition temperature

The ductile-brittle transition temperatures were determined for compatibilized nylon 6/acrylonitrile-butadiene-styrene (PA6/ABS) copolymer blends. The compatibilizers used for those blends were methyl methacrylate-co-maleic anhydride (MMA-MAH) and MMA-co-glycidyl methacrylate (MMA-GMA). The ductile-brittle transition temperatures were found to be lower for blends compatibilized through maleate modified acrylic polymers. At room temperature, the PA6/ABS binary blend was essentially brittle whereas the ternary blends with MMA-MAH compatibilizer were supertough and showed a ductile-brittle transition temperature at -10°C. The blends compatibilized with maleated copolymer exhibited impact strengths of up to 800 J/m. However, the blends compatibilized with MMA-GMA showed poor toughness at room temperature and failed in a brittle manner at subambient temperatures.

Dielectric and viscoelastic properties of cross-linked polyethylene aged under multi stressing conditions

Different measurements were performed in cross-linked polyethylene (XLPE) employed as insulating material in coaxial cables that were field-aged and laboratory-aged under multi-stressing conditions at room temperature. Samples were peeled from the XLPE cable insulation in three different positions: just below the external semiconductor layer (outer layer), in the middle (middle layer) and just above the internal semiconductor layer of the cable (inner layer). The imaginary part of the electric susceptibility showed three peaks that obey the Dissado-Hill model. For laboratory-aged XLPE samples peeled from the inner and from the middle positions the peak at very low frequency region increased while in samples from the outer position a quasi-DC conduction process was observed. In medium frequency range a broadening of the peak was observed for all samples. Viscoelastic properties determined through dynamic mechanical analysis suggested that the aging generates processes that promoted changes of the crystallinity and the cross-linking degrees of the polymer. Fourier transform infrared spectroscopy (FTIR) measurements revealed an increase of oxidation products (esters), evidence of polar residues of the bow-tie tree and the presence of cross-linking by-products (acetophenone). Optical and scanning electronic microscope (SEM) measurements in aged samples revealed the existence of voids and bow-tie trees that were formed during aging in the middle region of the cable.

Morphological, mechanical and thermal properties of nylon 6/ABS blends using glycidyl methacrylate-methyl methacrylate copolymers

Nylon6 is an attractive polymer for engineering applications because it has reactive functionality through amine and carboxyl end groups that are capable of reacting. For this reason, it has been used a lot in polymeric blends. Blends of nylon6/ABS (acrylonitrile-butadiene-styrene) were produced using glycidyl methacrylate-methyl methacrylate (GMA-MMA) copolymers as compatibilizer. The binary blends were immiscible and exhibited poor mechanical properties that stemmed from the unfavorable interactions among their molecular segments. This produced an unstable coarse phase morphology and weak interfaces between the phases in the solid state. The presence of the copolymer in the blends clearly led to a more efficient dispersion of the ABS phase and consequently optimized Izod impact properties. However, the compatibilized blend showed poor toughness at room temperature and failed in a brittle manner at subambient temperatures. © 2005 Springer Science + Business Media, Inc.

Color stability of resins and nylon as denture base material in beverages

Purpose: Staining of prosthodontic materials may result in patient dissatisfaction and additional expense for replacement. This study aimed to determine the color stability of two heat-cured denture base acrylic (Lucitone 550, Vipi Cril) and one nylon denture base resin (Transflex) after immersion in beverages. Materials and Methods: Forty disks of each resin (20.0-mm diameter, 3.0-mm thick) were prepared and stored in distilled water for 24 hours at 37°C. During that time (T 0), the color of all specimens was spectrophotometrically measured. Each specimen was immersed in coffee, cola, red wine, and distilled water as a means of control. After 15-day (T 1) and 30-day (T 2) periods of immersion, the color of the specimens was measured again. The CIE (Commission Internationale de L' Eclairage) L*a*b* system was used to determine mean ΔE (color changes) values for each material and compared statistically with two-way ANOVA and Bonferroni intervals at 0.95. Results: In ΔET 0T 1 and ΔET 0T 2 the most severe staining was apparent with red wine (p < 0.001), followed by coffee (p < 0.01), when compared to the specimens stored in distilled water. Transflex also showed significant color change after immersion in cola (p < 0.01). In ΔET 1T 2 only red wine promoted significant staining of all resins (p < 0.0001). Conclusion: Chromatic changes were exhibited by specimens immersed in red wine, followed by coffee. For Transflex, cola also promoted color changes. The values of color changes converted to National Bureau of Standard units showed them to be perceivable to the human eye. © 2011 by the American College of Prosthodontists.