"For good design, you pay now; for bad design, you pay later"--or do you?

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (leaves 117-118).What is the value of architectural design on office building income? This empirical study of 296 office building located in 11 Metropolitan Statistical Areas (MSA) hopes to quantitatively determine if a plain vanilla cereal box suburban office building commands more or less net operating income than an office building with a higher level of design. Previous empirical studies have found a strong influence of design on rents but were limited in geography, building characteristics and total number of observations. In an important study by Vandell and Lane (1990), they found that good architecture commanded a premium of over 20% in office rents. Also, their study showed that good design cost more to produce on average, but not necessarily in every case. Data was gathered from a portfolio of US office buildings and consisted of building metrics and property level 2000-2005 Net Operating Income (NOI). This base data set, MSA dummy variables and architectural attribute dummy variables (created by the authors) formed the backbone of the research. Multiple log linear regression analysis was conducted to identify the economic effects of good design.(cont.) In addition, a survey taken by 31 architects was used to capture subjective rankings on the all 296 office buildings to determine if there is a consensus as to what constitutes good design. It is hoped that these professionals, who are formally trained and are practicing in the field, are well-qualified to evaluate the design of each building. The survey results showed that the architects' responses are idiosyncratic and subjective. Not only did the individual participant's rankings show no significant relationship with one another, but also did not exhibit any relationship with actual building NOI. The empirical study found that the market paid a premium of 7.9% for buildings with non-center cores. Also, a significant 11.7-13.2% premium was paid for properties with non-rectangular and non-square shaped floor plans. Finally, buildings with 60% to 90% exterior windows commanded a substantial 10.7% premium. These results imply that better-designed buildings generate higher NOI either because the tenants are willing to pay a premium or because the operating costs of the building are less, or both.by Meena Murugappan and S. Michael O'Young, Jr.S.M

Quality of life in Type 1 (insulin-dependent) diabetic patients prior to and after pancreas and kidney transplantation in relation to organ function

Improvement of the quality of life in Type 1 (insulin-dependent) diabetic patients with severe late complications is one of the main goals of pancreas and/or kidney grafting. To assess the influences of these treatment modalities on the different aspects of the quality of life a cross-sectional study in 157 patients was conducted. They were categorized into patients pre-transplant without dialysis (n=29; Group A), pre-transplant under dialysis (n=44; Group B), post-transplant with pancreas and kidney functioning (n=31; Group C), post-transplant with functioning kidney, but insulin therapy (n=29; Group D), post-transplant under dialysis and insulin therapy again (n=15; Group E) and patients after single pancreas transplantation and rejection, with good renal function, but insulin therapy (n=9; Group F). All patients answered a mailed, self-administered questionnaire (217 questions) consisting of a broad spectrum of rehabilitation criteria. The results indicate a better quality of life in Groups C and D as compared to the other groups. In general the scores are highest in C, but without any significant difference to D. Impressive significant differences between C or D and the other groups were found especially in their satisfaction with physical capacity, leisure-time activities or the overall quality of life. The satisfaction with the latter is highest in C (mean±SEM: 4.0±0.2 on a 1 to 5-rating scale; significantly different from A: 3.1±0.1, B: 2.7±0.2 and E: 2.6±0.3; p<0.01), followed by D (3.8±0.2; significantly different from B and E; p<0.01). Group F shows a mean of 3.1±0.4, which is not significantly different from C. The percentages of patients in each group, who are not working: A: 38 %, B: 64 %, C: 74 %, D: 66 %, E: 87 % and F: 78 % indicate that there is no marked improvement in the vocational situation after successful grafting

Roles of Electrostatics and Conformation in Protein-Crystal Interactions

In vitro studies have shown that the phosphoprotein osteopontin (OPN) inhibits the nucleation and growth of hydroxyapatite (HA) and other biominerals. In vivo, OPN is believed to prevent the calcification of soft tissues. However, the nature of the interaction between OPN and HA is not understood. In the computational part of the present study, we used molecular dynamics simulations to predict the adsorption of 19 peptides, each 16 amino acids long and collectively covering the entire sequence of OPN, to the {100} face of HA. This analysis showed that there is an inverse relationship between predicted strength of adsorption and peptide isoelectric point (P<0.0001). Analysis of the OPN sequence by PONDR (Predictor of Naturally Disordered Regions) indicated that OPN sequences predicted to adsorb well to HA are highly disordered. In the experimental part of the study, we synthesized phosphorylated and non-phosphorylated peptides corresponding to OPN sequences 65–80 (pSHDHMDDDDDDDDDGD) and 220–235 (pSHEpSTEQSDAIDpSAEK). In agreement with the PONDR analysis, these were shown by circular dichroism spectroscopy to be largely disordered. A constant-composition/seeded growth assay was used to assess the HA-inhibiting potencies of the synthetic peptides. The phosphorylated versions of OPN65-80 (IC50 = 1.93 µg/ml) and OPN220-235 (IC50 = 1.48 µg/ml) are potent inhibitors of HA growth, as is the nonphosphorylated version of OPN65-80 (IC50 = 2.97 µg/ml); the nonphosphorylated version of OPN220-235 has no measurable inhibitory activity. These findings suggest that the adsorption of acidic proteins to Ca2+-rich crystal faces of biominerals is governed by electrostatics and is facilitated by conformational flexibility of the polypeptide chain

Hybrid system control using an on-line discrete event supervisory strategy

This paper describes a technique for synthesizing controllers for hybrid plants. Our modeling framework allows for the efficient online construction of limited lookahead discrete abstractions of the nonlinear continuous dynamics of the plant model. Discrete event supervisory controller synthesis techniques are used to construct a controller based on a DES specification and the abstracted plant model. The controller is advanced in a moving horizon approach. The modeling framework, synthesis techniques and the on-line computational strategy are discussed. A simple illustrative example is presented in detail and a realistic industrial application is outlined.Peer reviewed: YesNRC publication: Ye

Hybrid system modelong of tandem dynamically-positioned vessels

A Hybrid System model is used to aid the design and verification of a coordinated control system for two Dynamically Positioned marine vessels. A simple supervisory controller for the Emergency Shutdown and Disconnect operation is developed and verified using the automatic validation software HyTech.NRC publication: Ye

Discrete supervisory control of hybrid systems based on l- complete approximations

The topic of this paper is the synthesis of discrete supervisory control for hybrid systems Sigma with discrete external signals. Such systems are in general neither l- complete nor can they be represented by finite state machines. Our solution to the control problem is as follows: we find the strongest l-complete approximation (abstraction) Sigma (l) for Sigma, represent it by a finite state machine, and investigate the control problem for the approximation. If a solution exists on the approximation level, we synthesize the maximally permissive supervisor for Sigma (l). We show that it also solves the control problem for the underlying hybrid system Sigma. If no solution exists, approximation accuracy can be increased by computing the strongest k-complete abstraction Sigma (k), k > l. The basic ideas regarding the approximation step are explained within the framework of Willems' behavioral systems theory. Implementation issues are treated in a state space framework, and the main results are interpreted from a traditional control engineering point of view. copyright 2002 Kluwer Academic Publishers [accessed 2014 April 1st

On-line supervisory control of hybrid systems using embedded simulations

This paper describes a technique for synthesizing supervisory discrete event controllers for hybrid plants. The discrete event model of the plant behaviour is assembled for a limited lookahead horizon at run time based on discrete abstractions of embedded continuous simulations. A supervisory controller for this limited horizon model is then computed as a state avoidance problem. Since the controller is valid for only a limited time/event horizon, it must be re-computed on-line periodically, in order to extend the operation to an infinite time horizon. We present a scheme for enforcing guaranteed safe and nonblocking behaviour which is rooted in standard industrial practice.Peer reviewed: YesNRC publication: Ye

Supervisory control of hybrid systems via l-complete approximations

This contribution addresses the synthesis of supervisory control for hybrid systems with discrete external signals. Such systems are in general neither l-complete nor can they be represented by finite state machines. We find an l-complete approximation (abstraction) Σl for Σ, represent it by a finite state machine, and investigate the control problem for the approximation. If a solution exists, we synthesize the maximally permissive supervisor for Σl. We show that it also solves the control problem for the hybrid system Σ. If no solution exists, approximation accuracy can be increased by computing a k-complete abstraction Σk, k > l. This paper is entirely set within the framework of Willems' behavioural systems theory

Discrete supervisory control of hybrid systems based on l- complete approximations

The topic of this paper is the synthesis of discrete supervisory control for hybrid systems Sigma with discrete external signals. Such systems are in general neither l- complete nor can they be represented by finite state machines. Our solution to the control problem is as follows: we find the strongest l-complete approximation (abstraction) Sigma (l) for Sigma, represent it by a finite state machine, and investigate the control problem for the approximation. If a solution exists on the approximation level, we synthesize the maximally permissive supervisor for Sigma (l). We show that it also solves the control problem for the underlying hybrid system Sigma. If no solution exists, approximation accuracy can be increased by computing the strongest k-complete abstraction Sigma (k), k > l. The basic ideas regarding the approximation step are explained within the framework of Willems' behavioral systems theory. Implementation issues are treated in a state space framework, and the main results are interpreted from a traditional control engineering point of view