New Results on Multiple-Input Multiple-Output Broadcast Channels with Confidential Messages

This paper presents two new results on multiple-input multiple-output (MIMO) Gaussian broadcast channels with confidential messages. First, the problem of the MIMO Gaussian wiretap channel is revisited. A matrix characterization of the capacity-equivocation region is provided, which extends the previous result on the secrecy capacity of the MIMO Gaussian wiretap channel to the general, possibly imperfect secrecy setting. Next, the problem of MIMO Gaussian broadcast channels with two receivers and three independent messages: a common message intended for both receivers, and two confidential messages each intended for one of the receivers but needing to be kept asymptotically perfectly secret from the other, is considered. A precise characterization of the capacity region is provided, generalizing the previous results which considered only two out of three possible messages.Comment: Submitted to the IEEE Transactions on Information Theory, 11 pages, 5 figure

MIMO Gaussian Broadcast Channels with Confidential and Common Messages

This paper considers the problem of secret communication over a two-receiver multiple-input multiple-output (MIMO) Gaussian broadcast channel. The transmitter has two independent, confidential messages and a common message. Each of the confidential messages is intended for one of the receivers but needs to be kept perfectly secret from the other, and the common message is intended for both receivers. It is shown that a natural scheme that combines secret dirty-paper coding with Gaussian superposition coding achieves the secrecy capacity region. To prove this result, a channel-enhancement approach and an extremal entropy inequality of Weingarten et al. are used.Comment: Submitted to 2010 IEEE International Symposium on Information Theory, Austin, Texa

Health Start School-Based Clinic Staff and Hmong Adolescents: Does the Servant Leadership Theory Apply?

This pilot study investigated whether the staff at Health Start\u27s school-based clinics and the Hmong adolescents they serve are in agreement as to what health services Hmong adolescents want from the clinic and staff. In investigating this issue, servant leadership theory also was applied to answer the question: Does using servant leadership theory assist the staff in delivering culturally congruent healthcare to Hmong adolescents? According to Servant Leadership Theory, leaders first want to serve for the purpose of developing a healthier, wiser, freer, more autonomous follower. This theory, manifested by Robert K. Greenleaf through his work experiences and thinking about leadership issues, was applied to the staff and analyzed in order to understand how this theory will benefit them and their service delivery. This pilot study asked the following questions to answer how the services were perceived by Hmong adolescents and if the staff exhibited any traits of servant leadership: What kinds of comprehensive health services do the Hmong adolescents in the St. Paul schools want from the school-based clinic staff? What comprehensive health services does the staff think the Hmong adolescents want from the clinic and staff

A 'reality of return': the case of the Sarawakian-Chinese visiting China

Using an interpretive ethnographic framework, this paper focuses on how travel to the homeland informs the identity of the Sarawakian-Chinese, a diaspora that contains a composite of subcultures. The data collection is based upon 35 semi-structured interviews and participant observation of a Sarawakian-Chinese tour group to China. Whilst emotional connections with China are universally significant in constructing the diaspora's ethnic identity, the strength of association is influenced by characteristics of education, religion and language, as identity becomes re-defined and plural. The findings suggest that the influence of tourism to the homeland may not necessarily be significant in enhancing emotional and cultural connections with China. Instead, ambivalent connections to homeland become established during tourism experiences. Visits to the homeland could play a significant role in forging new and hybrid identities of ethnic communities outside the homeland, thereby bringing a new vital dimension to identity formation and communication of the Sarawakian-Chinese in the future

Distribution-free partial discrimination procedures

AbstractThis paper reviews discrimination procedures which provide distribution-free control over the individual misclassification probabilities. Particular emphasis is placed on the two-population rank method developed by Broffitt, Randles and Hogg, which utilizes the general formulation of Quesenberry and Gessaman. It is shown that the rank method extends from two to three or more populations in a natural and flexible fashion. A Monte Carlo study compares two suggested extensions with others proposed by Broffitt

Kondo effect in carbon nanotube quantum dots with spin-orbit coupling

Motivated by recent experimental observation of spin-orbit coupling in carbon nanotube quantum dots [F. Kuemmeth \textsl{et al.}, Nature (London) {\bf 452}, 448 (2008)], we investigate in detail its influence on the Kondo effect. The spin-orbit coupling intrinsically lifts out the fourfold degeneracy of a single electron in the dot, thereby breaking the SU(4) symmetry and splitting the Kondo resonance even at zero magnetic field. When the field is applied, the Kondo resonance further splits and exhibits fine multipeak structures resulting from the interplay of spin-orbit coupling and Zeeman effect. A microscopic cotunneling process for each peak can be uniquely identified. Finally, a purely orbital Kondo effect in the two-electron regime is also obtained.Comment: published version, 5 pages, 4 figure