In-Network Processing of Skyline Join Queries in Wireless Sensor Networks Using Synopses of Skyline Attribute Value Ranges.

We investigate the in-network processing of a skyline join query in wireless sensor networks (WSNs). While much research was conducted on processing skyline queries in WSNs, skyline join queries were dealt with only in traditional centralized or distributed database environments. However, such techniques cannot be applied to WSNs. Carrying out join filtering, as well as skyline filtering using them in WSNs, is infeasible due to limited memory in senor nodes and to excessive energy consumption in wireless communications. In this paper, we propose a protocol to process a skyline join query in WSNs energy efficiently with only a small amount of memory in each sensor node. It uses a synopsis of skyline attribute value ranges, which is a very compact data structure. The range synopsis is used both in the search of anchor points for skyline filtering and in 2-way semijoins for join filtering. We describe the structure of a range synopsis and present our protocol. To optimize our protocol, we solve some optimization problems. Through implementation and a set of detailed simulations, we show the effectiveness of our protocol. The range synopsis is confirmed to be compact enough for our protocol to work well with the limited memory and energy in each sensor node. For the correlated and random distributions, our protocol significantly outperforms other possible protocols, confirming the effectiveness of an in-network skyline as well as the join filtering capabilities of our protocol.

Switchable stimulated Raman scattering microscopy with photochromic vibrational probes.

Photochromic probes with reversible fluorescence have revolutionized the fields of single molecule spectroscopy and super-resolution microscopy, but lack sufficient chemical specificity. In contrast, Raman probes with stimulated Raman scattering (SRS) microscopy provides superb chemical resolution for super-multiplexed imaging, but are relatively inert. Here we report vibrational photochromism by engineering alkyne tagged diarylethene to realize photo-switchable SRS imaging. The narrow Raman peak of the alkyne group shifts reversibly upon photoisomerization of the conjugated diarylethene when irradiated by ultraviolet (UV) or visible light, yielding "on" or "off" SRS images taken at the photoactive Raman frequency. We demonstrated photo-rewritable patterning and encryption on thin films, painting/erasing of cells with labelled alkyne-diarylethene, as well as pulse-chase experiments of mitochondria diffusion in living cells. The design principle provides potentials for super-resolution microscopy, optical memories and switches with vibrational specificity.

High-Performance, Solution-Processable Thermally Activated Delayed Fluorescent Organic Light-Emitting Diodes Realized via the Adjustment of the Composition of the Organoboron Acceptor Monomer in Copolymer Host Materials.

Organic polymers that exhibit features pertinent to functioning as host materials for thermally activated delayed fluorescence (TADF) emitters have considerable potential in solution-processable organic light-emitting diodes (OLEDs), allowing simple, low-cost, and large-area applications. In particular, polymer hosts have superior characteristics, including facile functionality to introduce various electron donor and acceptor entities, the ability to uniformly disperse and contain small molecular dopants, and the ability to produce more smooth and homogeneous films, compared to those of their small-molecule counterparts. This manuscript describes the design and development of three new styrene-based copolymers (ABP91, ABP73, and ABP55) bearing diphenylacridine as the electron donor and 2,12-di-tert-butyl-7-phenyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene as the electron acceptor. In particular, ABP91, ABP73, and ABP55 were synthesized via variations in the ratio of donor to acceptor monomers to substantiate their influence in OLED applications. With the ability of the styrene backbone of interrupting the direct electronic coupling between the adjacent electron donor and acceptor entities through non-conjugated linkages, high triplet energy can be inherited by the resulting polymers (>2.70 eV). Furthermore, these materials manifest thermal robustness through high decomposition temperatures (between 348 and 366 °C) and high glass transition temperatures (between 234 and 277 °C). Consequently, solution-processable OLEDs fabricated using the newly synthesized copolymers as host materials and the familiar t4CzIPN as a green-emissive TADF dopant deliver state-of-the-art performance with maximum external quantum efficiencies of 21.8, 22.2, and 19.7% for ABP91, ABP73, and ABP55, respectively. To our knowledge, this is, to date, the best performance reported when organic polymers are used as host materials in solution-processable TADF OLEDs. The pragmatic outcomes obtained in this study can provide useful insights into the structure-property relationship to the OLED community for the further development of efficient polymer hosts for use in solution-processable TADF OLEDs.

Thermal Decomposition Study on Li2O2 for Li2NiO2 Synthesis as a Sacrificing Positive Additive of Lithium-Ion Batteries.

Herein, thermal decomposition experiments of lithium peroxide (Li2O2) were performed to prepare a precursor (Li2O) for sacrificing cathode material, Li2NiO2. The Li2O2 was prepared by a hydrometallurgical reaction between LiOH·H2O and H2O2. The overall reaction during annealing was found to involve the following three steps: (1) dehydration of LiOH·H2O, (2) decomposition of Li2O2, and (3) pyrolysis of the remaining anhydrous LiOH. This stepwise reaction was elucidated by thermal gravimetric and quantitative X-ray diffraction analyses. Furthermore, over-lithiated lithium nickel oxide (Li2NiO2) using our lithium precursor was synthesized, which exhibited a larger yield of 90.9% and higher irreversible capacity of 261 to 265 mAh g-1 than the sample prepared by commercially purchased Li2O (45.6% and 177 to 185 mAh g-1, respectively) due to optimal powder preparation conditions.

In-network processing of an iceberg join query in wireless sensor networks based on 2-way fragment semijoins.

We investigate the in-network processing of an iceberg join query in wireless sensor networks (WSNs). An iceberg join is a special type of join where only those joined tuples whose cardinality exceeds a certain threshold (called iceberg threshold) are qualified for the result. Processing such a join involves the value matching for the join predicate as well as the checking of the cardinality constraint for the iceberg threshold. In the previous scheme, the value matching is carried out as the main task for filtering non-joinable tuples while the iceberg threshold is treated as an additional constraint. We take an alternative approach, meeting the cardinality constraint first and matching values next. In this approach, with a logical fragmentation of the join operand relations on the aggregate counts of the joining attribute values, the optimal sequence of 2-way fragment semijoins is generated, where each fragment semijoin employs a Bloom filter as a synopsis of the joining attribute values. This sequence filters non-joinable tuples in an energy-efficient way in WSNs. Through implementation and a set of detailed experiments, we show that our alternative approach considerably outperforms the previous one.

In-network processing of joins in wireless sensor networks.

The join or correlated filtering of sensor readings is one of the fundamental query operations in wireless sensor networks (WSNs). Although the join in centralized or distributed databases is a well-researched problem, join processing in WSNs has quite different characteristics and is much more difficult to perform due to the lack of statistics on sensor readings and the resource constraints of sensor nodes. Since data transmission is orders of magnitude more costly than processing at a sensor node, in-network processing of joins is essential. In this paper, the state-of-the-art techniques for join implementation in WSNs are surveyed. The requirements and challenges, join types, and components of join implementation are described. The open issues for further research are identified.

Surface energy heterogeneity and heterogeneous adsorption of benzene on double-walled carbon nanotubes.

We examined the adsorption properties of double walled carbon nanotubes (DWCNTs) synthesized by using a catalytic chemical decomposition vapor method. To analyze the structural and energetical surface characteristics of the DWCNTs, nitrogen and benzene adsorption isotherms were measured. The Toth isotherm equation was used to correlate the adsorption data and evaluate the thermodynamic properties such as Henry's constant and the adsorption second virial coefficient. The existence of heterogeneous surface in DWCNTs was confirmed by the analysis of pore size distribution, the isosteric heat of adsorption, and the adsorption energy distribution determined for nitrogen and benzene.

[Family functioning and quality of life of the family care-giver in cancer patients].

PURPOSE: The purpose of this study was to identify the relationship among quality of life, family coherence, family hardiness, and family resources of the family care-giver caring for a cancer patient. METHOD: Data was collected by questionnaires from 137 families with a cancer patient at a General Hospital and Government Cancer Hospital. Data was analyzed using descriptive statistics, pearson correlation coefficients, and stepwise multiple regression. RESULTS: The score of quality of life showed a significant positive correlation with the score of the level of family sense of coherence, family hardiness, and family resources. The most powerful predictor of quality of life was sense of coherence and the variance was 30%. A combination of sense of coherence and family resources account for 34 % of the variance in quality of life of the family care-giver caring for a cancer patient. CONCLUSION: The results showed that family sense of coherence, hardiness, and family resources were significant influencing factors on the quality of life of the family care-giver caring for a cancer patient.

Heterogeneous adsorption of activated carbon nanofibers synthesized by electrospinning polyacrylonitrile solution.

This study focuses on the adsorption properties of activated carbon nanofibers (CNFs) fabricated by electrospinning polyacrylonitrile solutions dissolved in dimethylformamide, followed by heat treatment at high activation temperatures (700, 750, 800 degrees C). The samples were characterized by BET, SEM, and XRD. In addition, the adsorption energy distribution functions of CNFs were analyzed by using the generalized nonlinear regularization method. Comparative analysis of energy distribution functions provided significant information on the energetic and structural heterogeneities of CNFs. Furthermore, an investigation of adsorption equilibrium and kinetics of methylene blue (MB) and congo red (CR) revealed that the adsorption capacity and kinetics of MB are much higher and faster than that of CR on a given sample. Our experimental and theoretical results suggest that the CNFs used in this work may be widely used as an adsorbent.

Heterogeneity analysis of single-walled carbon nanotubes from the adsorption equilibria of nitrogen and benzene.

Nitrogen adsorption/desorption isotherms and gravimetric methods were employed to examine the structural and adsorption properties of selected adsorbent. The equilibrium data of benzene were also obtained at three different temperatures (303.15, 313.15, and 323.15 K) with pressures up to 7 kPa. The results of nitrogen and benzene sorption isotherm revealed that SWCNTs exhibit type II with the features of type I. The Toth and UNILAN models were found to provide a reasonable correlation between the adsorption isotherm data. In addition, the adsorption second virial coefficient and the isosteric heat of adsorption were determined by using these isotherm models. The isosteric heat of adsorption and adsorption energy distribution indicated that SWCNTs have energetically and structurally heterogeneous surfaces.

[Influencing factors on file-up stress of family caregivers with a family member having a chronic mental illness].

PURPOSE: The purpose of this study was to identify the factors influencing file-up family stress in the family with a family member having a chronic mental illness. METHOD: Data was collected by questionnaires from 365 families with a member having a chronic mental illness, in an outpatient clinic of a General Hospital and Government Psychiatric Hospital in Seoul. The data was analyzed using descriptive statistics, pearson correlation coefficients, and stepwise multiple regression. RESULT: The score of file-up stress showed a significantly negative correlation with the score of level of hardiness (r=-.31, p=.00), family support (r=-.13, p=.00), family cohesion (r=-.25, p=.00), and sense of coherence (r=-.26, p=.00). The most powerful predictor of file-up stress was family hardiness and the variance was 11.1%. A combination of hardiness, family support, and sense of coherence account for 14.8 % of the variance in file-up stress of the family with a member having a chronic mental illness. CONCLUSION: This study suggests that family support, hardiness, cohesion, and sense of coherence are significant influencing factors on file-up stress in the family with a member having a chronic mental illness.

[Prediction on the negative outcomes of anger in female adolescents].

PURPOSE: This study was designed to construct a structural model for explaining negative outcomes of anger in female adolescents. METHOD: Data was collected by questionnaires from 199 female adolescents ina female high school in Seoul. Data analysis was done with SAS for descriptive statistics and a PC-LISREL Program for Covariance structural analysis. RESULT: The fit of the hypothetical model to the data was moderate, thus it was modified by excluding 7 paths and adding free parameters to it. The modified model with the paths showed a good fit to the empirical data(chi2=5.62, p=.69, GFI=.99, AGFI=.97, NFI=.99, NNFI=1.01, RMSR=.02, RMSEA=.00). Trait anger, state anger, and psychosocial problems were found to have a significant direct effect on psychosomatic symptoms. State anger, psychosocial problems, and learning behaviors were found to have direct effects on depression of female adolescents. CONCLUSION: The derived model is considered appropriate for explaining and predicting negative outcomes of anger in female adolescents. Therefore, it can effectively be used as a reference model for further studies and is a suggested direction in nursing practice.

[Anger, problem behaviors, and health status in adolescent women].

PURPOSE: This cross-sectional study was designed to identify anger-expression types of adolescent women and investigate the relation between the identified anger-expression types and their problem behaviors and health status. METHOD: One hundred ninety nine high school freshmen were recruited from September to November, 2003. Data was analyzed using descriptive statistics, cluster analysis, chi(2)-test, ANOVA, and Duncan's multiple comparison test. RESULT: Three anger-expression types in adolescent women were found; Anger-out/in, Anger-control/in, and Anger- control type. Adolescent women with frequently using the anger-out/in type and with higher state anger reported more delinquent behaviors, more health risk behaviors, and higher psychosomatic symptoms. However, adolescent women with lower state anger and frequently using the anger-control type reported more depression scores. CONCLUSION: There is a need to further clarify the relationship between anger-expression types and depression in adolescent women. The findings suggest the necessity of a development of the program for lowering the anger level and controlling the unfavorable anger expression types such as the anger-out in.