Density,Crowding, and Factors Intervening in Their Relationship: Evidence from a Hyper-dense Metropolis

This paper, using survey data from 414 urban residents in Hong Kong, examines the effects of space, achieved privacy and satisfaction with living quarters on the perception of crowding. The results of this study suggest that occupants of spatial constrained dwellings do not necessarily feel crowded. While achieved privacy intervenes in the relationship between space and crowding, its effect is indirect and very moderate. Instead, the dissatisfaction with physical environment rather than with a quantity of space itself is a major cause of the feeling of crowdedness. These findings imply that architectural designs that meet the expectation of occupants may well alleviate feelings of crowdedness in situations of spatial constraint.     

Online bin packing of fragile objects with application in cellular networks

We study a specific bin packing problem which arises from the channel assignment problems in cellular networks. In cellular communications, frequency channels are some limited resource which may need to share by various users. However, in order to avoid signal interference among users, a user needs to specify to share the channel with at most how many other users, depending on the user’s application. Under this setting, the problem of minimizing the total channels used to support all users can be modeled as a specific bin packing problem as follows: Given a set of items, each with two attributes, weight and fragility. We need to pack the items into bins such that, for each bin, the sum of weight in the bin must be at most the smallest fragility of all the items packed into the bin. The goal is to minimize the total number of bins (i.e., the channels in the cellular network) used. We consider the on-line version of this problem, where items arrive one by one. The next item arrives only after the current item has been packed, and the decision cannot be changed. We show that the asymptotic competitive ratio is at least 2. We also consider the case where the ratio of maximum fragility and minimum fragility is bounded by a constant. In this case, we present a class of online algorithms with asymptotic competitive ratio at most of 1/4+3r/2, for any r>1. A preliminary version of this paper appeared in Proc. of Workshop on Internet and Network Economics (WINE’05, pp. 564–573). The research of W.-T.C. was supported in part by Hong Kong RGC grant HKU5172/03E. The research of F.Y.-L.C. was supported in part by Hong Kong RGC Grant HKU7142/03E. The research of D.Y. was supported by NSFC (10601048). The research of G.Z. was supported in part by NSFC (60573020).     

Optimal tree structure with loyal users and batch updates

We study the probabilistic model in the key tree management problem. Users have different behaviors. Normal users have probability p to issue join/leave request while the loyal users have probability zero. Given the numbers of such users, our objective is to construct a key tree with minimum expected updating cost. We observe that a single LUN (Loyal User Node) is enough to represent all loyal users. When 1−p≤0.57 we prove that the optimal tree that minimizes the cost is a star. When 1−p>0.57, we try to bound the size of the subtree rooted at every non-root node. Based on the size bound, we construct the optimal tree using dynamic programming algorithm in O(n⋅K+K ⁴) time where K=min {4(log (1−p)⁻¹)⁻¹,n} and n is the number of normal users.     

Multivariate Stochastic Volatility Models with Correlated Errors

We develop a Bayesian approach for parsimoniously estimating the correlation structure of the errors in a multivariate stochastic volatility model. Since the number of parameters in the joint correlation matrix of the return and volatility errors is potentially very large, we impose a prior that allows the off-diagonal elements of the inverse of the correlation matrix to be identically zero. The model is estimated using a Markov chain simulation method that samples from the posterior distribution of the volatilities and parameters. We illustrate the approach using both simulated and real examples. In the real examples, the method is applied to equities at three levels of aggregation: returns for firms within the same industry, returns for different industries, and returns aggregated at the index level. We find pronounced correlation effects only at the highest level of aggregation.     

Three Lenses on Occupations and Professions in Organizations: Becoming,Doing, and Relating

Management and organizational scholarship is overdue for a reappraisal of occupations and professions as well as a critical review of past and current work on the topic. Indeed, the field has largely failed to keep pace with the rising salience of occupational and professional (as opposed to organizational) dynamics in work life. Moreover, not only is there a dearth of studies that explicitly take occupational or professional categories into account, but there is also an absence of a shared analytical framework for understanding what occupations and professions entail. Our goal is therefore two-fold: first, to offer guidance to scholars less familiar with this terrain who encounter occupational or professional dynamics in their own inquiries and, second, to introduce a three-part framework for conceptualizing occupations and professions to help guide future inquiries. We suggest that occupations and professions can be understood through lenses of “becoming”, “doing”, and “relating”. We develop this framework as we review past literature and discuss the implications of each approach for future research and, more broadly, for the field of management and organizational theory.     

Women on boards and bank efficiency in ASEAN-5: the moderating role of the independent directors

Corporate governance codes around the world promote women’s presence in corporate board. The extant literature suggests women directors contribute to improve monitoring and advisory role of the board. This study aims to examine the role of independent women directors in improving banks’ efficiency. Using 102 commercial banks from ASEAN-5 countries for a period of 1999–2012, we run generalized method of moments models to test the relationship between the variables. Our results show that banks with independent women directors on board contribute significantly to the bank’s efficiency level. Contrary to the literature, we found that the appointment of women directors or independent directors alone does not significantly enhance banks’ efficiency. The result suggests that women directors are more effective on boards if they are also appointed as independent directors. This finding implies that a combination of corporate governance mechanism is more powerful than relying on a single element of corporate governance.     

Psychological antecedents and motivational models of collective action: examining the role of perceived effectiveness in political protest participation

The present study examines Hong Kong citizens’ willingness to participate in the Occupy Central/Umbrella Movement. A representative adult survey (N = 816) was conducted before the Occupy Central protest in 2014. Regression analyses showed that the core psychological antecedents of political identity (psychological attachment to pro-democracy parties and Occupy activists), political efficacy (perceived effectiveness of individual and movement agency), ideology (dissatisfaction with the pace of democratization), and emotion (anger with the political environment) were significant predictors of likely participation. Measures of perceived effectiveness of the Occupy movement to achieve successful outcomes (i.e. its ability to influence public opinion, strengthen the pro-democracy cause in Hong Kong, and facilitate opinion expression) explained additional variance even after controlling for demographics and the core antecedents. An integrated motivational model of collective action was then tested using structural equation modeling. Findings are consistent with the extant literature. Moral convictions (democracy as a fundamental human value) served as an antecedent of identity, efficacy, ideology, and anger, while identity exhibited direct and indirect effects on participation through efficacy, ideology and anger. The model also pointed to a role for perceived effectiveness, supporting the idea that individuals are motivated by other potential outcomes of a protest beyond achieving its primary objective.     

Transforming Access to Research Literature for Developing Countries

Abstract

The economic development of a country depends heavily on its scientific strength and ability to resolve problems in such areas as public health, infectious disease, environmental management, or industrial progress. Access to research information traditionally depends on ability to pay, which has a negative impact on developing countries. A number of new initiatives address this imbalance, ranging from consortial licensing and new publishing models to the Open Access Initiative, and have the ability to meet the needs of research in financially constrained countries. The advent of the Open Access strategies, particularly interoperable institutional archives, has the potential to revolutionize access to essential research.     

Nonparametric inference for the joint distribution of recurrent marked variables and recurrent survival time

Time between recurrent medical events may be correlated with the cost incurred at each event. As a result, it may be of interest to describe the relationship between recurrent events and recurrent medical costs by estimating a joint distribution. In this paper, we propose a nonparametric estimator for the joint distribution of recurrent events and recurrent medical costs in right-censored data. We also derive the asymptotic variance of our estimator, a test for equality of recurrent marker distributions, and present simulation studies to demonstrate the performance of our point and variance estimators. Our estimator is shown to perform well for a wide range of levels of correlation, demonstrating that our estimators can be employed in a variety of situations when the correlation structure may be unknown in advance. We apply our methods to hospitalization events and their corresponding costs in the second Multicenter Automatic Defibrillator Implantation Trial (MADIT-II), which was a randomized clinical trial studying the effect of implantable cardioverter-defibrillators in preventing ventricular arrhythmia.