Hierarchical information clustering by means of topologically embedded graphs

We introduce a graph-theoretic approach to extract clusters and hierarchies in complex data-sets in an unsupervised and deterministic manner, without the use of any prior information. This is achieved by building topologically embedded networks containing the subset of most significant links and analyzing the network structure. For a planar embedding, this method provides both the intra-cluster hierarchy, which describes the way clusters are composed, and the inter-cluster hierarchy which describes how clusters gather together. We discuss performance, robustness and reliability of this method by first investigating several artificial data-sets, finding that it can outperform significantly other established approaches. Then we show that our method can successfully differentiate meaningful clusters and hierarchies in a variety of real data-sets. In particular, we find that the application to gene expression patterns of lymphoma samples uncovers biologically significant groups of genes which play key-roles in diagnosis, prognosis and treatment of some of the most relevant human lymphoid malignancies

Understanding user interaction problems with wireless connection via research through design

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University LondonPeople frequently have problems making multiple devices work together. In this thesis, I use the Research‐through‐Design approach to understand the issues and propose solutions. Through an iterative series of investigations, the problems people have with the connection of multiple devices has been examined, including usability issues, difficulties with the sequential connection procedure, and difficulties performing an action. I found non‐expert users to have difficulties with interpreting and evaluating the devices’ interaction status regarding the sequence of the connection procedure. When an evaluation problem occurs, they have problems dealing with the required sequence or diagnosing the error in their interactions. The problem understanding was examined from additional cases. The comprehension of the problems allowed me to generate design implications and propose a design solution. I proposed two implications with which to solve the stated problem. I suggested helping users evaluate device interaction and reduce unnecessary user interactions. A design framework was suggested as a solution by providing diagrammatic representations of system interaction and signals revealing device status. I then assessed the suggested solutions using paper prototypes, and demonstrated their effectiveness. The improved interfaces helped users evaluate device connection status so they may determine how to proceed with sequential interaction. With the Research‐through‐Design approach constructing knowledge by integrating theories and hypothesis, I found the feature of user‐multiple device interaction in which a user is required to manage the interaction between the devices. A single device cannot aid the user interaction. In the dissertation, I proposed a desirable state of user interaction, which is achieved by two devices revealing connection states together so that a user can earn a useful system image

Longitudinal Pantothenic Acid Status of Pregnant and Lactating Women

Pantothenic acid nutritional status was evaluated in a cohort of twenty-nine Caucasian pregnant women, aged 20-35, during their third trimester of pregnancy, at two-weeks postpartum and at three months postpartum. Seventeen non-pregnant, non-lactating women who had similar demographic backgrounds as the pregnant women were selected as a control group and followed the same experimental schedule as the pregnant women. A fasting blood sample, two days 24-h urine specimens and diet record were obtained for each of two days from each subject at each period. The mean dietary pantothenic acid intakes of the women during pregnancy (5.30±1.74 mg/day) and during lactation (8.90±11.66 mg/day) were statistically similar to that of the control group (9.63±19.74 mg/day). A substantial number of the study population consumed less than 4 mg pantothenic acid daily. The average of 2.75 mg dietary pantothenic acid intake per 1000 kcal was consistent in all groups. The mean fasting blood level (406.38±78.21 ng/ml) and urinary excretion (3.21±0.88 mg/day, 3.85±1.24 mg/g creatinine) of the pregnant women were significantly lower than those of the control group (530.14±157.90 ng/ml; 4.38±3.69 mg/day, 5.78±4.90 mg/g creatinine). The suppressed panthothenic acid levels in blood and urinary excretion during pregnancy were increased to levels comparable to controls during the nursing period. Pantothenic acid lev~s in the biological fluids correlated significantly with dietary intake. A bound form of pantothenic acid was not detected in the plasma and plasma values were relatively constant. Thus, plasma was suggested as an insensitive indicator of pantotheriic acid nutritional status. The mean pantothenic acid contents of fore and hind milk samples were 2.60 microgram/ml, 2.44 microgram/ml, respectively and were not statistically different. Overall, the pregnant women consumed less than the suggested level of pantothenic acid, maintained lower blood levels and had decreased urinary excretion