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Ventricular fibrillation (VF) is a type of cardiac arrhythmia. This chaotic cardiac electrical activity results in heart quivering instead of normal pumping. To date, early cardiopulmonary resuscitation (CPR) and defibrillation are the only effective VF treatment. Acute myocardial infarction is the most common cause of VF, and cardiomyopathy, myocarditis, electrolyte imbalance, cardiotoxic medication, and even ion channel abnormality can cause VF. Physicians have attempted to identify specific patterns in electrocardiography (ECG) that might predict VF in the short term. For example, ST segment changes might imply coronary artery occlusion with myocardial ischemia, increasing VF risk. However, in most cases, VF occurs abruptly without any early warning. Machine learning is used to extract information usually neglected by the human brain. In deep learning, a cascade of multiple layers of processing is used to extract features. Machine learning is used to classify different types and outcomes of cardiac arrhythmias that are difficult to recognize directly. In this study, we developed a new deep learning method to predict the onset of VF. ECG from MIT-BIH databases were used as the training and validation data sets; the prediction results showed that the proposed two-dimensional short-time Fourier transform (2D STFT)/continuous wavelet transform (CWT) convolutional neural network (CNN) model can reach a recall of 99% and an accuracy of 97%. We also compared the proposed 2D model with 1D and 2D time-domain CNN models. The results showed that the 1D CNN and 2D time-domain models can achieve an accuracy of 60.5% and 56%, respectively.

As evidence regarding the impact of preceding medications on resuscitation outcomes has been inconsistent, this study aimed to analyze the association between preceding medications and resuscitation outcomes in patients experiencing out-of-hospital cardiac arrest (OHCA). This retrospective study included patients with OHCA presenting to a tertiary care hospital by emergency medical service (EMS) between January 2006 and June 2011. Using the Utstein template, data were collected from EMS and hospital medical records for prehospital care, in-hospital care, and medications which were taken continuously for at least 2 weeks preceding OHCA. Primary outcome was the proportion of patients with a survived event. Multivariable logistic regression analyses were performed to evaluate the predictors of survived events. Among the 1381 included patients with OHCA, 552 (40.0%) patients achieved sustained return of spontaneous circulation and 463 (33.5%) patients survived after resuscitation, 96 (7.0%) patients survived until discharge, and 20 (1.4%) patients had a favorable neurological outcome at discharge. The multivariable analyses revealed that use of statins preceding OHCA was independently associated with a greater probability of a survived events (OR=2.09, 95% CI 1.08 to 4.03, p=0.028).Use of digoxin was adversely associated with survived events (OR=0.39, 95% CI 0.16 to 0.90, p=0.028) in patients with OHCA. The continuous use of statins preceding OHCA was positively associated with survived events, while use of digoxin was adversely related. It deserves more attention on medications preceding OHCA because of their potential effect on resuscitation outcomes.

This research reinvestigates the detection of atrial fibrillation (AF) from a recurrent neural network (RNN) viewpoint. In particular, a long short-term memory (LSTM) model of RNN is designed to exploit the high-order spectral and temporal features of the multi-lead electrocardiogram (ECG) signals of patients with AF. To verify the proposed method, the LSTM model is tested with ECG data available from the PhysioNet and some normal ECG data collected in our labs. The results show that not only the deviation of the so-called RR intervals of ECG signals but also its temporal variations are critical to AF detection. The accuracy of AF detection can reach up to 98.3 %, with an LSTM model of using 30 hidden units. Considering more realistic applications, we further tested the model with subjects different from that of the training data. The accuracy is about 87% with high sensitivity. The experimental results show that the proposed model is able to effectively extract both the long-term and short-term characteristics of the spectral content of the AF ECG signals, making it a good candidate model for AF detection.

Immunomagnetic reduction (IMR) is a method to assay biomolecules by utilizing antibody functionalized magnetic nanoparticles. For clinical validation, important analytic performances of assaying carcinoembryonic antigen (CEA) using IMR are characterized. Furthermore, IMR is applied to assay carcinoembryonic antigen (CEA) in human serum for clinical validation. A total of 118 healthy controls and 79 patients with colorectal cancer (CRC) are recruited in this study. For comparison, assays using chemiluminometric immunoassay (CLIA) are also done for quantizing CEA in these serum samples. The results reveal a high correlation in terms of serum CEA concentration detected via IMR and CLIA is found (r = 0.963). However, IMR shows higher clinical sensitivity and specificity than those of CLIA. Moreover, the rate of false positives for smoking subjects is clearly reduced through the use of IMR. All the results demonstrate IMR is a promising alternative assay for serum CEA to diagnose CRC.

The bankruptcy event of Lehman Brothers and the corresponding global economic recession in 2008 and 2009, influenced the electricity load demand patterns for which traditional load forecasting approaches were not able to effectively predict. To overcome this problem, this paper proposes a new hybrid economic indices based short-term load forecasting (HEI-STLF) system. In which business indicators, such as the leading index or the coincide index, each combined with stock index as hybrid economic indices influencing factors for the support vector regression (SVR) model, to respond to the economic dynamics and reduce its impact on forecasting accuracy. The Taiwan island-wide electricity load demands from 2008 to 2011 are used as the case study for performance testing with different combinations of the Taiwan business indicator and the Taiwan Stock Exchange Capitalization-Weighted Stock Index (TAIEX). The results show that the proposed HEI-STLF system with hybrid economic indices of an annualized six-month rate of change of composite leading index and a 90 days moving average of TAIEX, achieves the best forecasting performance. Compared to the traditional SVR load forecasting approach, it improves the forecasting accuracy in the best condition by 30.39% in the period when the load demands are affected by the global economic recession.

Many efforts in past years have been made to lower the linguistic barriers for non-native English speakers to access the Internet. Internet standard RFC 3490, referred to as IDNA (Internationalizing Domain Names in Applications), focuses on access to IDNs (Internationalized Domain Names) in a range of scripts that is broader in scope than the original ASCII. However, the use of character variants that have similar appearances and/or interpretations could create confusion. A variant IDL (Internationalized Domain Label), derived from an IDL by replacing some characters with their variants, should match the original IDL; and thus a variant IDN does. In RFC 3743, referred to as JET (Joint Engineering Team) Guidelines, it is suggested that zone administrators model this concept of equivalence as an atomic IDL package. When an IDL is registered, an IDL package is created that contains its variant IDLs generated according to the zone-specific Language Variant Tables (LVTs). In addition to the registered IDL, the name holder can request the domain registry to activate some of the variant IDLs, free or by an extra fee. The activated variant IDLs are stored in the zone files, and thus become resolvable. However, an issue of scalability arises when there is a large number of variant IDLs to be activated. In this article, the authors present a resolution protocol that resolves the variant IDLs into the registered IDL, specifically for Han character variants. Two Han characters are said to be variants of each other if they have the same meaning and are pronounced the same. Furthermore, Han character variants usually have similar appearances. It is not uncommon that a Chinese IDL has a large number of variant IDLs. The proposed protocol introduces a new RR (resource record) type, denoted as VarIdx RR, to associate a variant expression of the variant IDLs with the registered IDL. The label of the VarIdx RR, denoted as the variant index, is assigned by an indexing function that is designed to give the same value to all of the variant IDLs enumerated by the variant expression. When one of the variant IDLs is accessed, Internet applications can compute the variant index, look up the VarIdx RRs, and resolve the variant IDL into the registered IDL. The authors examine two sets of Chinese IDLs registered in TWNIC and CNNIC, respectively. The results show that for a registered Chinese IDL, a very small number of VarIdx RRs, usually one or two, are sufficient to activate all of its variant IDLs. The authors also represent a Web redirection service that employs the proposed resolution protocol to redirect a URL addressed by a variant IDN to the URL addressed by the registered IDN. The experiment results show that the proposed protocol successfully resolves the variant IDNs into the registered IDNs.

Data broadcasting is independent of arrivals of requests, and thus it is suitable to transmit popular videos that may interest many viewers at a particular period of time. One broadcasting method (called periodic broadcasting) is to divide a popular video into segments, which are then simultaneously broadcast on different data channels. Once clients want to watch the video, they download the segments from these channels. Specially, the greedy disk-conserving broadcasting (GDB) scheme supports a client with a small bandwidth. In comparison with other similar schemes such as the skyscraper broadcasting (SkB) and the client-centric approach (CCA) schemes, the GDB clients have smaller waiting time. Extending GDB, this work designs a reverse GDB (RGDB) scheme to achieve small buffering spaces as well as low bandwidths at the client. We further mathematically prove that RGDB still guarantees on-time video delivery at small client bandwidths. A formula is derived for the maximum number of segments buffered by an RGDB client. Finally, an analysis shows that RGDB has 33-50% smaller client buffer requirements than GDB in most situations.

A popular video can be broadcast by partitioning the video into segments, which are broadcast on several channels simultaneously and periodically. This method allows multiple users to share channels, leading to higher bandwidth utilization. Previous studies mainly focus on reducing viewers' waiting time. This work studies another important issue, namely client buffer. When the term "client buffer" is used, it means the worst-case buffer requirements (i.e., the maximum value). savings. A reverse fast broadcasting (RFB) scheme is proposed to alleviate the buffer problem. There are two specific properties for RFB. First, this scheme arranges the segments in descending order of their numeric indices on each channel at the server end. Second, RFB requires a client to receive segments as late as possible, such that the client buffers the smallest number of segments. RFB has the same waiting time as the fast broadcasting (FB) scheme, but just needs a half of buffer spaces required by FB. RFB also requires smaller client buffers than the pyramid broadcasting (PB), skyscraper broadcasting (SkB), greedy disk-conserving broadcasting (GDB), BroadCatch, and recursive frequency-splitting schemes. Moreover, if we apply the same changes to the PB, SkB and GDB schemes, their buffer requirements decrease by 25% to 75%

To support an increasing amount of various new applications in vehicular ad hoc networks (VANETs), routing protocol design has become an important research challenge. In this paper, we propose a Bipolar Traffic Density Awareness Routing (BTDAR) protocol for vehicular ad hoc networks. The BTDAR aims at providing reliable and efficient packets delivery for dense and sparse vehicle traffic network environments. Two distinct routing protocols are designed to find an optimal packet delivery path in varied vehicular networks. In dense networks, a link-stability based routing protocol is designed to take vehicles connectivity into consideration in its path selection policy and maximize the stability of intervehicle communications. In sparse networks, a min-delay based routing protocol is proposed to select an optimal route by analyzing intermittent vehicle connectivity and minimize packets delivery latency. Intervehicles connectivity model is analyzed. The performance of BTDAR is examined by comparisons with three distinct VANET routing protocols. Simulation results show that the BTDAR outperforms compared counterpart routing protocols in terms of packet delivery delay and packet delivery ratio.

Most cases of obturator hernia are diagnosed during surgery for treatment of acute small bowel obstruction resulting from incarceration. We present the case of a patient with incarcerated obturator hernia that was correctly diagnosed by computed tomography preoperatively. Laparoscopic preperitoneal mesh repair of the incarcerated obturator hernia and a contralateral direct inguinal hernia found incidentally was successfully performed.

Laparoscopic appendectomy is one of the most commonly performed laparoscopic procedures. Impact of previous abdominal surgery on laparoscopic appendectomy has not been previously reported. From January 2001 to December 2005, 2029 patients with clinically suspected acute appendicitis underwent laparoscopic surgery in our hospital. Of these, 234 patients (11.5%) were found to have other pathology by intraoperative or histologic findings and were excluded from the study. The 1795 patients who underwent laparoscopic appendectomy for acute appendicitis were divided into three groups: group 1, patients without a history of previous abdominal surgery (n = 1652, 92%); group 2, patients with a history of upper abdominal surgery (n = 20, 1.1%); group 3, patients with a history of lower abdominal surgery (n = 123, 6.8%). Data were collected retrospectively by chart review and analyzed for conversion rate, operative time, intraoperative and postoperative complications, and hospital stay. Of the 1795 patients, 13 (0.7%) were converted to open appendectomy because of technical difficulty. Overall mean operative time was 57.2 (range, 20–225) min. There was no mortality or intraoperative complications. Overall postoperative complication rate was 10.7% (n = 193): rate of surgical wound infection was 8.2 % (n = 147), surgical wound seroma 1.3% (n = 24), and intra-abdominal abscess 0.8% (n = 14). Overall postoperative hospital stay averaged 3.2 (range, 0–39) days. There were no significant differences between the three groups regarding the conversion rate (0.8% vs. 0% vs. 0%, p = 0.567), operative time (57.3 vs. 55.8 vs. 56.9 min, p = 0.962), postoperative complication rates (10.7 vs. 10 vs. 12.2%, p = 0.863), and hospital stay (3.2 vs. 3.6 vs. 3.1 days, p = 0.673). Previous abdominal surgery, whether upper or lower abdominal, has no significant impact on laparoscopic appendectomy for acute appendicitis.

One way of broadcasting a popular video is partitioning the video into segments, each being broadcasted on several streams periodically. The approach alleviates the bandwidth thirsty in real-time video broadcasting without sacrificing viewers' waiting time by allowing multiple users to share the same video segments. One representative scheme of the category is the recursive frequency-splitting (RFS) broadcasting scheme, which yields approximate minimum waiting time. In this paper, a novel approach is introduced to enhance RFS, called Smooth RFS (SRFS), in which the approaches of segment patching and asynchronous downloading-playing are proposed for achieving a smooth broadcast of variable-bit-rate (VBR) -encoded videos. The design of SRFS aims to reduce the peak bandwidth consumption and variance during the distribution of VBR videos in order to achieve better upper bounds on the bandwidth peak and the variance. Extensive simulation has been conducted on the proposed scheme by comparing a number of past reported counterparts, including the trace-adaptive fragmentation (TAF) scheme and the smooth fast broadcasting (SFB) scheme. The results indicate that the proposed scheme yields lower bandwidth peak and variance. Besides, given a fixed bandwidth that is smaller than the peak, SRFS obtains a much smaller blocking rate than that of the other schemes.

The composition of traditional domain names are restricted to ASCII letters, digits, and hyphens (abbreviated as LDH). This makes it difficult for many to use their native language to name and access their Internet hosts. The IETF IDN (Internationalized Domain Name) Working Group proposes a mechanism, IDNA (Internationalizing Domain Names in Applications), for internationalized access to multilingual domain names. The proposal uses a preparation process that converts a Unicode IDN into an ACE (ASCII Compatible Encoding) string that uses only LDH. Thus, applications can look up the ACE string by using the existing DNS infrastructure. However, some of the domain name strings embedded in multilingual content do not have any charset tag so they cannot appropriately be converted into ACE strings. We noticed that many Internet applications allow users to use non-ASCII domain names. We were motivated to design an architecture for IDN resolution as well as to minimize the cost of modifying legacy Internet applications. We specifically focus on designing an IDN server proxy, which is located on the domain name server side, to handle domain names in multiple encodings. In this article, we study several architecture design issues including detection of charset encoding, routing of non-ACE IDN lookup requests, and so on.With respect to these design issues, we present an IDN server proxy architecture which stores ACE IDNs in domain name servers. Note that traditional domain name servers can be used without modification. An IDN server proxy, called Octopus, is employed on the domain name server side. Octopus converts a non-ACE IDN string into ACE upon receiving an IDN lookup request from remote users or autonomous systems. The ACE string is then forwarded to backend domain name servers (where the traditional domain names and ACE IDNs are stored) for further processing. This allows Internet users to access IDNs without having to upgrade their software.Based on the design and implementation of Octopus, we deployed a CDN (Chinese domain name) trial in July 2002. In this article, we present the results of testing Octopus IDN lookup functions as well as our experiences in providing CDN Web services. Several types of errors can occur if applications are unable to handle IDNs adequately. For example, a Web browser may erroneously parse an IDN within a URL. Many legacy Web servers are unable to process the IDN of a virtual host. Web application servers may have trouble completing some actions such as redirecting Web pages to alternative Web pages. Our studies help service providers understand potential problems when non-ASCII domain names are used and the best common practice at this stage. As well, the experiences give some guidance for software developers to develop IDNA-compliant Internet applications.

One way to broadcast a popular video is to partition the video into segments, which are broadcasted on several streams periodically. The approach lets multiple users share streams; thus, the stress on the scarce bandwidth can be alleviated without sacrificing viewers' waiting time. One representative approach is the Staircase Broadcasting (SB) scheme, which requires buffering only 25% of a playing video. However, the scheme mainly supports transmission of CBR-encoded videos. In this paper, we proposed a simple VBR staircase broadcasting (SVSB) scheme, which can distribute VBR-encoded videos with small buffers. The idea behind the scheme is asynchronous downloading and playing, and hybrid division by length and size. It is simple and effective. We also applied the design to several segmented broadcasting schemes, such as the harmonic-based broadcasting, and the recursive frequency-splitting (RFS) schemes, to enable them to support VBR videos. A simulation was conducted to evaluate the schemes. The results indicated that the SVSB scheme still outperforms on required buffers, and disk transfer rate at client end. The harmonic broadcasting scheme with VBR support consumes the least bandwidth.

Femoral vein catheterization is often carried out during resuscitation and in critical care units. It is usually achieved via a blind, external landmark-guided technique, through manual localization of the femoral artery. However, this approach can be challenging in patients with severe shock because of absence or ambiguity of the arterial pulse. We report a case of inadvertent cannulation, with a large-bore catheter, of the right femoral artery, which was mistaken as a venous route for medication and massive transfusion. The large cannula caused direct mechanical obstruction, while intra-arterial medications induced vascular injury and vasospasm. Both factors led to thrombosis and occlusion of the right external iliac artery, thus jeopardizing the distal blood supply, and ultimately resulting in muscle necrosis of the involved limb, and the need for thrombectomy and extensive fasciotomy to salvage the extremity. This case highlights that correct placement of a central venous catheter should be clearly ascertained before the catheter is used for medical treatment, especially when catheterization is performed in shock status.

An archive is a file containing several related files. Many Internet resources, such as freeware, shareware and trail software, are often packaged into archives for easy installation and taking. Additionally, thousands of users search for archives and download them from different sources everyday. In this paper, previous research on archive downloading is extended via proxy cache to support archive searching. Internet proxy cache servers are used to gather a significant number of Web pages, detect those that contain archive links, and then use the obtained data to search archives by description or filename. Two schemes, iterative and backtracking, are proposed to obtain Web pages with archive links. The experimental results indicate that the precision that both of the schemes can achieve is about the same; however, the backtracking scheme reduces the number of checked pages by a factor of 26. Finally, a real system was implemented to demonstrate the proposed approaches.

Presents a framework for deciding on a good execution strategy for a given program based on the available data and task parallelism in the program on PC laboratory clusters. Proposes a virtual cluster scheduling scheme to take account of the relationships between tasks for task parallelism, and also processor speed, processor load and network environment to balance load for data parallelism in a PC cluster environment. The approach is very effective in terms of the overall execution time, and demonstrates the feasibility of automatic cluster assignment, processor set selection and data partition functions for data and task parallel programs.

Traditionally, file transfer protocol (FTP) servers are major archive providers and users apply the Archie server to locate FTP archives. With the extreme popularity of the WWW, Web servers are now important archive providers and users download archives via HTTP. To reduce HTTP traffic, proxy cache servers are deployed on the Internet. However, we find the hit rate of archives in cache servers is quite low. This study proposes a combination of caching and better searching mechanisms to alleviate the problem. We enable a proxy server to automatically collect WWW and FTP archives from its cache, organize them in the form of an FTP directory, and then offer the directory list to the Archie. Accordingly, users can find archives on WWW and FTP servers through the Archie, and they can directly download archives from the proxy server, thus improving the reuse of cached archives. A system was implemented and operated in a real environment to evaluate the approach and results are discussed.

The World Wide Web (WWW) has become an extremely popular information service. Large HTTP packets result in network congestion. Proxy cache servers are widely deployed on the Internet to overcome this obstacle. However, the approach yields an undesirable phenomenon – a small set of users misuse proxy servers to mirror the entire contents of Web sites. This behavior wastes network resources, increases WWW servers’ loads, increases users’ waiting time, and violates copyrights. Approaches to designing a proxy server with WWW usage control and to making the proxy server effective on local area networks are proposed to prevent such abnormal WWW access and to prioritize WWW usage. Finally, a system, ProxyBreaker, is implemented to demonstrate the approaches. The implementation reveals that the proposed approaches are effective, such that the abnormal Web access does not reoccur.

In a distributed system, any clock synchronization algorithm has to synchronize the clocks periodically to maintain the accuracy of network time. The uncertainty of network delays and the unknown relative drift rate between computer's clocks are two major problems to synchronize clocks. Increasing the messages (clock readings) exchange rate can reduce the drift error, but it will increase the network load. If the network becomes congested, it will increase the delay uncertainty and the cell loss rate. This will decrease the synchronization accuracy. Therefore, it is a problem to predict as to how fast one needs to exchange the clock messages to achieve an expected accuracy of network time. We present a simple clock synchronization algorithm. Suppose the delay uncertainty and cell loss rate are given, we can clearly know how fast the message exchange rate can achieve and how accurate is the network time. Even though our measurement results show that the stability of our current computer clocks is worse than most assumptions in the literature on clock synchronization, our clock synchronization algorithm can still provide high synchronization accuracy by accurately estimating the relative drift rate between clocks. Here we also show how to monitor the quality of synchronization online.

In order to approach a video-on-demand (VOD) service, we can allocate more bandwidth to broadcast a popular video more frequently to reduce viewers' waiting time. Using a broadcasting scheme to support a popular video periodically, in order to guarantee a given waiting time, the harmonic broadcasting scheme needs the least bandwidth in the existing schemes. In this paper, we show that using any broadcasting scheme, the minimum bandwidth requirement for the same waiting time is the same as the harmonic broadcasting scheme. Therefore, for a popular video, in order to approach a near VOD service, the harmonic broadcasting scheme is an optimal broadcasting scheme that needs the least bandwidth for a given viewers' waiting time.

As we support video-on-demand (VOD) service with batching schemes, the bandwidth requirement will be very large for a popular movie. For a hot video, fast data broadcasting scheme substantially reduce the bandwidth requirements as compared with batching schemes. However, the fast data broadcasting scheme needs to predict which movie is hot. If the prediction is not accurate, the allocated bandwidth will be wasted. This paper presents a new data broadcasting scheme for VOD service. For a movie, as it is popular, the new scheme will work like the fast data broadcasting scheme to save the communication bandwidth. If there is no request for the movie, the new scheme will not allocate bandwidth for the movie. Therefore, the bandwidth allocation for a movie is always efficient whether or not the movie is popular.

For a popular movie, in order to minimize the service delay with a given bandwidth, currently the harmonic broadcasting scheme can provide users with the shortest waiting time to approach near video-on-demand service. This paper presents an enhanced scheme, which can improve the bandwidth utilization and reduce further the viewers' waiting time.

Using multiple channels to broadcast a popular video can reduce the viewer's waiting time to approach video-on-demand service. For a given bandwidth allocation, pyramid broadcasting schemes can provide users with shorter waiting time as compared with conventional broadcasting schemes. However, for a 120-minute movie, the waiting time is only reduced to 20 minutes as we allocate 4 video channels for the movie. The harmonic broadcasting scheme can reduce the waiting time to 4 minutes but it can not support the live telecast. This paper presents a new broadcasting scheme, which can support live videos and reduce the waiting time to 8 minutes for the above case. With the same waiting requirement for a hot video, the new scheme can greatly reduce the bandwidth requirements and provide heterogeneous users' services.

Facsimiles have become the most popular form of text communication on the public switched telephone network (PSTN). At the same time, the e-mail is the well-liked textual delivery system on computer networks. The message exchange between the fax/phone and e-mail will improve their availability and increase their messaging capabilities. In the Distributed System Laboratory at the National Central University, ROC, a new system integrating the MIME (multipurpose internet mail extensions) mail and fax/phone has been proposed and implemented to fulfil the requirements of bidirectional multimedia messaging. A user can send mails from Internet to PSTN. Furthermore, our system allows transmitting multimedia messages from PSTN to Internet. The system has the following properties: (1) only use the usual current equipments, e.g. telephones, G3 fax machines and personal computers, (2) be conformable to the popular protocols and existing systems, (3) provide user-friendly interfaces, such as the voice guided help, and (4) provide a universal and transparent addressing scheme between facsimiles and e-mail. Finally, we believe that our system meets real user needs.

For a 120-minute popular movie, with 4 video channels, current digital video broadcasting systems can support the movie every 30 minutes. Suppose the set-top box at client end can buffer portions of the playing video on disk. Pyramid broadcasting schemes can support the movie every 19 minutes. We present a new data broadcasting and receiving scheme, which can service the movie every 8 minutes. For a given bandwidth allocation, the new scheme greatly reduces the viewer waiting time. The disk space and transfer rate requirements of the set-top box are also reduced to be feasible.