3,341 research outputs found
Usability Evaluation And Correspondence Analysis Of Smartphone Operating Systems
User-centered smartphone interface design is important so that consumers can easily learn about and begin to use newly purchased smartphones. This study first evaluates the effectiveness, efficiency, and user satisfaction of smartphone interfaces in Taiwan in terms of two representational operating systems: Android and iPhone OS. The usability evaluation includes observational experiments, user questionnaires, and the Wilcoxon sign-rank test. This study then conducts the correspondence analysis to summarize positive/ negative evaluations of usage and specification for smartphone OS. In observational experiments, a total of 48 participants with no previous smartphone experience on using smartphone with Android and iPhone OS are asked to perform five common phone tasks. All experiments are recorded and observed. Results and observations are discussed to attain a closer match between user needs and the performance of smartphone OS
Efficient Downlink Channel Reconstruction for FDD Multi-Antenna Systems
In this paper, we propose an efficient downlink channel reconstruction scheme
for a frequency-division-duplex multi-antenna system by utilizing uplink
channel state information combined with limited feedback. Based on the spatial
reciprocity in a wireless channel, the downlink channel is reconstructed by
using frequency-independent parameters. We first estimate the gains, delays,
and angles during uplink sounding. The gains are then refined through downlink
training and sent back to the base station (BS). With limited overhead, the
refinement can substantially improve the accuracy of the downlink channel
reconstruction. The BS can then reconstruct the downlink channel with the
uplink-estimated delays and angles and the downlink-refined gains. We also
introduce and extend the Newtonized orthogonal matching pursuit (NOMP)
algorithm to detect the delays and gains in a multi-antenna multi-subcarrier
condition. The results of our analysis show that the extended NOMP algorithm
achieves high estimation accuracy. Simulations and over-the-air tests are
performed to assess the performance of the efficient downlink channel
reconstruction scheme. The results show that the reconstructed channel is close
to the practical channel and that the accuracy is enhanced when the number of
BS antennas increases, thereby highlighting that the promising application of
the proposed scheme in large-scale antenna array systems
Onsite Early Prediction of PGA Using CNN With Multi-Scale and Multi-Domain P-Waves as Input
Although convolutional neural networks (CNN) have been applied successfully to many fields, the onsite earthquake early warning by CNN remains unexplored. This study aims to predict the peak ground acceleration (PGA) of the incoming seismic waves using CNN, which is achieved by analyzing the first 3 s of P-wave data collected from a single site. Because the amplitude of P-wave data of large and small earthquakes can differ, the multi-scale input of P-wave data is proposed in this study in order to let the CNN observe the input data in different scales. Both the time and frequency domains of the P-wave data are combined into multi-domain input, and therefore the CNN can observe the data from different aspects. Since only the maximum absolute acceleration value of the time history of seismic waves is the target output of the CNN, the absolute value of the P-wave time history data is used instead of the raw value. The proposed arrangement of the input data shows its superiority to the one directly inputting the raw P-wave data into the CNN. Moreover, the predicted PGA accuracy using the proposed CNN approach is higher than the one using the support vector regression approach that employed the extracted P-wave features as its input. The proposed CNN approach also shows that the accuracy of the predicted PGA and the alert performances are acceptable based on data from two independent and damaging earthquakes
Factors that influence survival in colorectal cancer with synchronous distant metastasis
AbstractBackgroundTreatments for the purposes of curing or more effectively managing metastatic colorectal cancer (CRC) are evolving. Our study focused on patients with primary CRC with synchronous distant metastasis, and we analyzed the factors influencing patient survival.MethodsData review was conducted retrospectively. Clinicopathological parameters included age, sex, site of primary cancer, tumor cell differentiation, number of liver metastasis, presence of extrahepatic metastasis, treatment of liver metastasis, pre-treatment carcinoembryonic antigen (CEA) level, status of treatment response, salvage treatment and survival.ResultsA total of 420 patients were identified and considered for our study. Of those, 275 patients (65.4%) had liver-only metastasis, 100 patients (23.8%) had concomitant lung metastasis, and 40 patients (9.5%) had other metastases. Additionally, 145 patients (34.5%) had liver-directed treatment including surgical resection (28.5%), radiofrequency ablation (RFA) (10.6%) and transcatheter arterial chemoembolization (TAE) (1.2%). There were 80 patients (19%) with CEA levels < 10, 135 patients (32.1%) with CEA 10–100, and 165 patients (39.2%) with CEA > 100. There were 200 patients (47.6%) who had received chemotherapy, 130 patients (30.9%) with target therapy, and 40 patients (9.5%) who had not undergone any salvage treatment. Three significant factors were identified, including treatment of liver metastasis (p=0.027), pre-treatment CEA (p=0.04), and salvage treatment (p=0.005).ConclusionWe demonstrated three factors influencing patient survival including treatment of liver metastasis, pre-treatment CEA level, and salvage treatment. Aggressive treatment of liver metastasis including surgical resection or RFA combined with chemotherapeutic agents appear to provide an increased rate of survival to patients
Osteomyelitis of Multiple Lumbar Vertebrae Associated with Infected Aortic Aneurysm: A Case Report
A 73-year-old male patient presented with a pulsating abdominal mass and intractable low back pain for several days. Magnetic resonance imaging revealed an infected abdominal aortic aneurysm invading the second, third, and fourth lumbar vertebrae. He underwent radical debridement of the infected aneurysm with reconstruction using vascular bypass, partial corpectomy of the L2 to L4 vertebrae, anterior reconstruction with autogenous fibular shaft, and posterior instrumentation with posterolateral fusion. Culture of the necrotic tissues grew oxacillin-resistant Staphylococcus aureus. He received intravenous vancomycin infusion for 4 weeks and oral ciprofloxacin for 6 months postoperatively. After a 15-month follow-up, no apparent signs of further infection were noted. C-reactive protein and erythrocyte sedimentation rate returned to normal during follow-up. No neurologic symptoms other than mild low back soreness were noted. The stability of the lumbar spine was maintained using long segment reconstruction with autogenous fibula shaft and posterior instrumentation along with posterolateral fusion. Infected aortic aneurysm with vertebral osteomyelitis is a rare clinical entity. Prompt diagnosis and adequate treatment are essential
Understanding the Impact of Service Failure and Recovery Justice on Consumers’ Satisfaction and Repurchase Intention
This research attempts to explore the impacts of different types of justice and their interactions on the satisfaction toward service failure recovery. We attempt to classify justices into hygiene, motivator, or asymmetric variable, based on the concept of asymmetric effect and two factors theory proposed by Herzberg. Specifically, we predict that procedural and distributive justices are hygiene or performance factor and interpersonal justice is motivator. In addition, based on expectancy-disconfirmation theory (EDT), we also attempt to understand the interaction between paired justices by arguing that motivator can generate more effect when hygiene factor or performance factors meet initial expectation. An experiment, with 3x2x2 between-subjects factorial design consisting of three factors to represent different levels of justice provided by online retailer, will be conducted to test the proposed hypotheses. A two-step approach will be used to (1) confirmation the types (hygiene, performance, or motivator) that each justice dimension belongs to, (2) understand the impact of each justice on satisfaction, and (3) test whether motivator will generate more effect when hygiene and performance factor are satisfied
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