Predefined Events Research Articles

Risk of Arterial Thrombotic Events in Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) have an increased risk of venous thrombotic events. The risk of arterial thrombotic events in IBD, however, has been less well characterized. We explored whether Crohn's disease (CD) and ulcerative colitis (UC) are associated with a higher risk for thrombotic events involving the mesenteric, cardiac, or cerebral arteries. Using the Thomson Reuters MarketScan Research claims database, we conducted a retrospective cohort study of IBD patients observed for the occurrence of pre-defined thrombotic events. For comparison, four non-IBD controls were age-, sex-, and index date-matched to each IBD case. The outcomes of interest were acute mesenteric ischemia, transient ischemic attack, cerebrovascular occlusion, atherosclerosis, peripheral vascular disease, and myocardial infarction. We performed a multivariate analysis adjusting for potential confounders for thrombotic events, including hypertension, diabetes, hyperlipidemia, and, in women, the use of contraceptives. We calculated the adjusted hazard ratios (HRs) for each event by comparing IBD patients with controls and used the log-rank test to determine statistical significance. The study included 17,487 IBD patients and 69,948 controls. Overall, IBD patients had a markedly increased risk of acute mesenteric ischemia (HR=11.2, P<0.001). IBD patients as a whole did not have an increased risk of other arterial thrombotic events, including myocardial infarction and transient ischemic attack, when compared with controls. However, women with IBD who were over the age of 40 years had a higher risk of myocardial infarction (HR=1.6, P=0.003). In addition, women with IBD below the age of 40 years who showed a significantly higher risk for stroke (HR=2.1, P=0.04). For all events, the risks in CD and UC were similar. Patients with IBD have a markedly increased risk of acute mesenteric ischemia. Subgroup analysis reveals that women over the age of 40 years with IBD are at increased risk of myocardial infarction, whereas those below the age of 40 years exhibit a two-fold higher risk for stroke. In contrast, men with IBD did not share these same risks for arterial thrombotic events.

Broadcast Court-Net Sports Video Analysis Using Fast 3-D Camera Modeling

This paper addresses the automatic analysis of court-net sports video content. We extract information about the players, the playing-field in a bottom-up way until we reach scene-level semantic concepts. Each part of our framework is general, so that the system is applicable to several kinds of sports. A central point in our framework is a camera calibration module that relates the a-priori information of the geometric layout in the form of a court model to the input image. Exploiting this information, several novel algorithms are proposed, including playing-frame detection, players segmentation and tracking. To address the player-occlusion problem, we model the contour map of the player silhouettes using a nonlinear regression algorithm, which enables to locate the players during the occlusions caused by players in the same team. Additionally, a Bayesian-based classifier helps to recognize predefined key events, where the input is a number of real-world visual features. We illustrate the performance and efficiency of the proposed system by evaluating it for a variety of sports videos containing badminton, tennis and volleyball, and we show that our algorithm can operate with more than 91% feature detection accuracy and 90% event detection.

Event detection intelligent camera development

A new camera system ‘event detection intelligent camera’ (EDICAM) is being developed for the video diagnostics of W-7X stellarator, which consists of 10 distinct and standalone measurement channels each holding a camera. Different operation modes will be implemented for continuous and for triggered readout as well. Hardware level trigger signals will be generated from real time image processing algorithms optimized for digital signal processor (DSP) and field programmable gate array (FPGA) architectures. At full resolution a camera sends 12 bit sampled 1280 × 1024 pixels with 444 fps which means 1.43 Terabyte over half an hour. To analyse such a huge amount of data is time consuming and has a high computational complexity. We plan to overcome this problem by EDICAM's preprocessing concepts. EDICAM camera system integrates all the advantages of CMOS sensor chip technology and fast network connections. EDICAM is built up from three different modules with two interfaces. A sensor module (SM) with reduced hardware and functional elements to reach a small and compact size and robust action in harmful environment as well. An image processing and control unit (IPCU) module handles the entire user predefined events and runs image processing algorithms to generate trigger signals. Finally a 10 Gigabit Ethernet compatible image readout card functions as the network interface for the PC. In this contribution all the concepts of EDICAM and the functions of the distinct modules are described.

클럽의 길이 변화에 따른 골프 스윙의 지면반력 변화

Proper weight shifting is essential for a successful shot in golf swing and this could be described by means of the ground forces between the feet and ground. It is assumed that the ground forces would different according to the club used because the length and swing weight of each club is different. But, in present, it is not clear what changes are made by the change of clubs and this affect the swing motion. Therefore this study focused on the investigation of the changes of the ground forces and ground reaction forces (GRF) by the change of club length. The subjects were three professional male golfers. Four swings (driver, iron 3, iron 5, and iron 7) for each subject were taken by two high speed video cameras and two AMTI force platforms were used to measure the GRF simultaneously. Kwon GRF 2.0 and Mathcad 13 software were used to post processing the data. Changes of the three major component of GRF (Vertical, lateral, anterior-posterior force) at 10 predefined events were analyzed including the maximum. Major findings of this study were as follows. 1. Vertical forces; - There were no significant changes until the top of backswing. - Maximum was occurred at the club horizontal position in the downswing for both feet. The shorter club produced more maximum forces than longer ones in the left foot, but reverse were true for the right foot. - Maximum forces at impact shows the same patterns. 2. Lateral forces; Maximum was occurred at the club horizontal position for both feet, but there were no lateral forces because the direction of two forces was different. Maximum force pattern by different clubs was same as the vertical component. 3. Anterior-posterior forces; - This component made a counter-clock wise moment about a vertical axis located between two foot until the club vertical position was reached during the backswing, and reverse moment were produced when the club reached horizontal at the downswing. - Also this component made a forward moment about a horizontal axis located in the CG during the fore half of the downswing, and a reverse moment until the club reached vertical at the follow through phase. Maximum was occurred at the club vertical in the downswing for both feet. The longer club produced more maximum forces than shorter ones for both feet.

Low Diagnostic Yield of Electrocardiogram Testing in Younger Patients With Syncope

Routine ECG testing is recommended in the evaluation of syncope, although the value of such testing in young patients is unclear. For ECG testing, we assess the diagnostic yield (frequency that ECG identified the reason for syncope) and predictive accuracy for 14-day cardiac events after an episode of syncope as a function of age. Adult patients with syncope or near-syncope were prospectively enrolled for 1 year at a single academic emergency department (ED). A 3-physician panel reviewed ED charts, hospital records, and telephone interview forms to identify predefined cardiac events. The primary outcome included all 14-day, predefined cardiac events including arrhythmia, myocardial ischemia, and structural heart disease. Of 592 eligible patients, 477 (81%) provided informed consent. Direct telephone contact or admission/outpatient records were successfully obtained for 461 (97%) patients, who comprised the analytic cohort. There were 44 (10%) patients who experienced a 14-day cardiac event. Overall diagnostic yield of ECG testing was 4% (95% confidence interval 2% to 6%). For patients younger than 40 years, ECG testing had a diagnostic yield of 0% (95% confidence interval 0% to 3%) and was associated with a 10% frequency of abnormal findings. ECG testing in patients younger than 40 years did not reveal a cardiac cause of syncope and was associated with a significant frequency of abnormal ECG findings unrelated to syncope. Although our findings should be verified in larger studies, it may be reasonable to defer ECG testing in younger patients who have a presentation consistent with a benign cause of syncope.

A 12-week, multicenter, randomized, partially blinded, active-controlled, parallel-group study of budesonide inhalation suspension in adolescents and adults with moderate to severe persistent asthma previously receiving inhaled corticosteroids with a metered-dose or dry powder inhaler

Nebulized budesonide inhalation suspension (BIS) is approved in the United States for children with asthma aged 1 to 8 years. The primary objective of this study was to compare the efficacy of BIS 0.5 mg QD and 2.0 mg BID in terms of the mean change from baseline to end of treatment in predose forced expiratory volume in 1 second (FEV1). In this 12-week, partially blinded, randomized study, subjects aged >or=12 years with moderate to severe persistent asthma previously receiving inhaled corticosteroids (ICSs) by dry powder inhaler (DPI) or metered-dose inhaler (MDI) continued therapy during a 2- to 3-week run-in period and then switched to BIS 0.5 mg QD, 1.0 mg QD, 1.0 mg BID, or 2.0 mg BID, or budesonide DPI 400 microg BID (active reference arm). Besides FEV1 (the primary variable), other outcome variables included changes in forced vital capacity (FVC) from baseline to weeks 4, 8, and 12 and to the average over the treatment period; as well as changes from baseline to the end of treatment in diary-collected daytime and nighttime asthma symptom scores, rescue medication use, nighttime awakenings due to asthma, morning and evening peak expiratory flow (PEF), percentages of symptom-free and medication-free periods, and the incidence of predefined asthma events. Adverse events were recorded by subjects. Steady-state pharmacokinetics of budesonide were assessed in all treatment arms. Efficacy analyses included data in a modified intent-to-treat approach. Differences in the change from baseline to end of treatment in FEV1 were assessed using analysis of covariance (ANCOVA). For secondary variables, changes from baseline to each visit or to the treatmentperiod average were compared among groups using an ANCOVA model. P <or= 0.05 was considered statistically significant. The randomized population consisted of 758 subjects: 57 (7.5%) aged 12 to <17 years, 667 (88.0%) aged 17 to <65 years, and 34 (4.5%) aged >or=65 years. There was no significant difference in mean change in predose FEV1 between BIS 0.5 mg QD and BIS 2.0 mg BID (0.02 vs 0.01 L). On average, mean values for the BIS dosage groups did not indicate any deterioration from baseline to the treatment period for variables associated with asthma control such as FEV1, FVC, daytime and nighttime asthma symptom scores, rescue medication use, nighttime awakenings, morning and evening PEF, percentages of symptom-free and rescue medication-free periods, and predefined asthma events. The BIS 1.0-mg BID treatment appeared to be closest to budesonide DPI in plasma budesonide concentrations and improvement in predose FEV1 (0.08 vs 0.12 L). All treatments were well tolerated. In this study, no difference in efficacy between BIS 2.0 mg BID and 0.5 mg QD was found in adolescents and adults with persistent asthma when transitioned from ICSs delivered with a DPI or MDI. Subjects taking all BIS dosages experienced similar responses for variables associated with asthma control.

Older Age Predicts Short‐Term, Serious Events After Syncope

To assess the relationship between age and 14-day serious events after an emergency department (ED) visit for syncope. One-year prospective cohort study. Single academic ED. Adult patients with an ED complaint of syncope or near-syncope. Treating physicians prospectively recorded the presence or absence of potential risk factors for serious clinical events. Patients were contacted by telephone at 14 days for a structured interview. A three-physician panel reviewed ED charts, hospital records, and telephone interview forms to identify predefined events. The primary outcome included any 14-day predefined event. A secondary outcome included any 14-day predefined event that was first diagnosed after the initial ED visit. Age was analyzed in 20-year intervals. Multivariate logistic regression controlled for baseline demographic, comorbidity, and electrocardiogram data. Of 592 eligible patients, 477 (81%) provided informed consent. Follow-up was successfully obtained for 463 (97%) patients. The age range was 18 to 96, and 47% of patients were aged 60 and older. There were 80 (17%) patients who had a 14-day event, including 18 (4%) with a delayed diagnosis. Compared with patients aged 18 to 39, the adjusted odds ratio (OR) of a serious outcome was 2.7 (95% confidence interval (CI)=0.9-8.4) for patient aged 40 to 59, 3.8 (95% CI=1.3-12) for patients aged 60 to 79, and 3.8 (95% CI=1.2-12) for patients aged 80 and older. Age of 60 and older is strongly associated with short-term serious events after an ED visit for syncope.

An Effective Algorithm for Automatic Detection and Exact Demarcation of Breath Sounds in Speech and Song Signals

Automatic detection of predefined events in speech and audio signals is a challenging and promising subject in signal processing. One important application of such detection is removal or suppression of unwanted sounds in audio recordings, for instance in the professional music industry, where the demand for quality is very high. Breath sounds, which are present in most song recordings and often degrade the aesthetic quality of the voice, are an example of such unwanted sounds. Another example is bad pronunciation of certain phonemes. In this paper, we present an automatic algorithm for accurate detection of breaths in speech or song signals. The algorithm is based on a template matching approach, and consists of three phases. In the first phase, a template is constructed from mel frequency cepstral coefficients (MFCCs) matrices of several breath examples and their singular value decompositions, to capture the characteristics of a typical breath event. Next, in the initial processing phase, each short-time frame is compared to the breath template, and marked as breathy or nonbreathy according to predefined thresholds. Finally, an edge detection algorithm, based on various time-domain and frequency-domain parameters, is applied to demarcate the exact boundaries of each breath event and to eliminate possible false detections. Evaluation of the algorithm on a database of speech and songs containing several hundred breath sounds yielded a correct identification rate of 98% with a specificity of 96%

Complications of the Cox-II inhibitors parecoxib and valdecoxib after cardiac surgery

Conclusion: Patients treated with coronary artery bypass grafting and who have Parecoxib and Valdecoxib utilized for postoperative pain control had an increased incidence of postoperative cardiovascular events. Summary: There is serious concern that, in nonsurgical settings, use of Cox-II inhibitors increases risk of thromboembolic events long-term. The authors sought to evaluate the safety of Parecoxib and Valdecoxib after coronary artery bypass grafting. This was a randomized, double-blind study. After coronary artery bypass grafting, patients were treated for ten days and followed for thirty days. The Cox-II inhibitors used in this study were Valdecoxib (Bextra, Pfizer) and its intravenous prodrug Parecoxib (Dymastat, Pfizer). After coronary artery bypass grafting, patients were randomly assigned to receive intravenous Parecoxib for at least three days followed by oral Valdecoxib through day ten or were assigned to be treated with intravenous placebo followed by oral Valdecoxib, or placebo, for ten days. There were 1,671 patients enrolled in the study and all patients also had access to opiate based medications. The primary endpoint was the frequency of pre-defined adverse events (cardiovascular events, renal failure or dysfunction, gastroduodenal ulceration, and wound-healing complications). Compared to the group given placebo alone, the groups given Parecoxib and Valdecoxib, placebo and Valdecoxib, and placebo and Valdecoxib, all had higher rates of confirmed adverse events (4.0% in the placebo group versus 7.4% in each of the coxib groups; risk ratio for each comparison, 1.9; 95% CI, 1.1-3.2; P =.02). Cardiovascular events including myocardial infarction, cardiac arrest, stroke, and pulmonary embolism were particular more frequent among patients given Parecoxib and Valdecoxib (2.0% versus 0.5%; risk ratio 3.7; 95% CI, 1.0-13.5; P =.03). Comment: Previous data on the adverse effects of Cox-II inhibitors has focused on long- term thromboembolic risk. There has been data to suggest Cox-II inhibitors could exert significant opiate sparing effects after surgical procedures. The current study, however, suggests patients with coronary artery disease who undergo CABG may be adversely impacted by the use of Cox-II inhibitors to control perioperative pain. While no such data currently exists to implicate Cox-II inhibitors and increased cardiovascular complications after peripheral vascular surgery, the current data may imply Cox-II inhibitors should be avoided in patients undergoing peripheral vascular surgery as well.

Tracking-based event detection for CCTV systems

This paper presents a description of an event detection algorithm based on trajectories designed for closed-circuit television (CCTV) surveillance systems. Following the foreground segmentation, blob and scene basic characteristics—blob position or speed and people density—are used to create low-level descriptions of predefined events. Comparing sequence parameters with the semantic description of the events associated with the current scenario, the system is able to detect them and raise an alert signal to the operator, the final decision-maker. In the approach presented here, the specific demands for CCTV surveillance systems applied to public transport environments will be analysed, together with the appropriate image processing techniques in order to build an intelligent surveillance system able to detect “potentially dangerous situations.”

Advanced Surveillance: From Tracking To Event Detection

The authors suggest an automatic surveillance system based on a robust and simple algorithm for foreground detection and tracking of multiple objects in complex environments. It is possible to obtain enough information from the characteristics of the detected objects, their centroid's position and their trajectories as to detect some predefined events. Working without the operator supervision the application analyses the video streams from the CCTV surveillance system, discarding empty scenes for monitoring or recording, showing to the operator those fulfilling predefined requirements, like crowding, and rising an alarm to call the operator attention when it decides that an event may be taking place. The application is based on very simple algorithms in order to allow a single computer the analysis of up to eight video streams in real-time. Blob and scene characteristics are used to create a low-level description of predefined events. The application detects events by comparing the sequence's parameters with those associated with the events for the current scenario. The provided examples are tailored to the specific demands of a surveillance system in a public transport environment.

The efficacy and safety of valsartan-based versus amlodipine-based treatment in elderly patients with isolated systolic hypertension: the Val-Syst study

To compare the therapeutic efficacy and tolerability of the angiotensin II receptor blocker valsartan with that of the dihydropyridine calcium channel blocker amlodipine in elderly patients with isolated systolic hypertension. The primary endpoint was to show that equipotency in systolic blood pressure reduction is accompanied by superiority in tolerability profile (on pre-selected, class-related adverse events) of valsartan-based treatment. This was a multicenter, double-blind, randomized, parallel-group study. Following a 2-week placebo run-in period, 421 elderly patients aged from 60 to 80 years (mean, 69 years) with isolated systolic hypertension (SBP 160 to 220 mmHg with DBP < 90 mmHg) recruited from 35 outpatient settings in Italy, received valsartan 80 mg (n = 208) or amlodipine 5 mg (n = 213) once daily. After 8 weeks of double-blind treatment, patients with poorly controlled BP were uptitrated to valsartan 160 mg or amlodipine 10 mg once daily. If after further 8 weeks systolic BP was still >= 140 mmHg, low dose hydrochlotothiazide was added. Valsartan-based and amlodipine-based treatments were equally effective in reducing SBP: mean SBP/DBP reductions were -33.4/-6.0 mmHg versus -33.5/-6.5 mmHg, respectively. SBP control (<140 mmHg) was achieved in 74.7% of patients on valsartan and 73.0% of patients on amlodipine. The mean SBP/DBP levels achieved at week 24 were 136.4/77.6 and 136.3/77.2 mmHg, respectively, in the valsartan and amlodipine groups and the mean pulse pressure was 58.8 and 59.1 mmHg, respectively. Pre-defined class-related adverse events were observed in 21.6% of patients on valsartan, compared with 31.9% of patients on amlodipine (p=0.0086), including 4.8% versus 27.2% for peripheral edema (p<0.0001). No patient in the valsartan group withdrew from the study because of symptomatic leg edema, whereas 9 patients on amlodipine had symptomatic leg edema which led to discontinuation of treatment. There were no laboratory adverse events attributed to valsartan or amlodipine, and no significant ECG changes. Valsartan and amlodipine are both highly effective in controlling BP in patients with isolated systolic hypertension. However, valsartan offers a significant tolerability advantage as it shows a reduced risk of developing adverse events.

A Laboratory Evaluation of an Auditory Display Designed to Enhance Intraoperative Monitoring

Encouraged by the popularity of the pulse oximeter pulse-tone, we developed and tested an auditory display of six physiologic variables. The display consisted of a cardiovascular sound triggered by every heartbeat (conveying heart rate) and a respiratory sound triggered by every breath (conveying respiratory rate). Attributes of the cardiovascular sound were modulated to convey hemoglobin saturation and blood pressure, and those of the respiratory sound were modulated to denote end-tidal CO2 and tidal volume. Three display formats (auditory, visual, and combined) were compared. Fourteen anesthesia residents monitored dynamic displays of 6 variables to detect and identify 6 predefined events during 21 trials. An event occurred during each trial and the subject’s task was to detect when it started and then identify the type of event. Subjects detected every event. They detected events more rapidly with the combined display (10.4 s) than with the visual (12.8 s) or auditory (13.0 s) displays. Subjects correctly identified events least often with the auditory display (60% versus visual 88% and combined 80%). They correctly identified events more quickly with the combined display than with the visual display. We conclude that, with little training, clinicians can successfully detect and identify simulated clinical events using an auditory display of six variables.

Pacemaker systems as implantable cardiac rhythm monitors

Pacemaker systems as implantable cardiac rhythm monitors

Admission plasma glucose. Independent risk factor for long-term prognosis after myocardial infarction even in nondiabetic patients.

To investigate whether a relationship exists between admission plasma glucose level and long-term outcome in nondiabetic patients after an acute myocardial infarction. This was a retrospective study with prospective follow-up of 197 consecutive nondiabetic patients with acute myocardial infarction followed for 1.5-2.5 years at the Department of Cardiology at Karolinska Hospital. The mean admission plasma glucose level was 8.15 +/- 3.0 mmol/l. During follow-up, 60 (30%) patients died, 20 (10%) were rehospitalized for heart failure, 12 (6%) were rehospitalized for nonfatal reinfarction, and 79 (40%) had at least one of these events. In univariate analysis, admission plasma glucose level was significantly higher in patients who had any of the predefined events than in those without these events. In a multivariate Cox proportional hazard regression model that allowed for confounding baseline predictors, admission plasma glucose level was an independent predictor of nonfatal reinfarction (P = 0.006), hospitalization for heart failure (P = 0.0034), and a major cardiovascular event (P = 0.0042) and was of borderline significance for death during long-term follow-up (P = 0.09). Admission plasma glucose level in nondiabetic patients with acute myocardial infarction seems to be an independent predictor of long-term outcome. This indicates that an elevated admission plasma glucose level not only reflects acute stress, but also may be a marker of disturbed glucose metabolism that worsens the prognosis and requires intervention.

Incidence and determinants of mortality and cardiovascular events in diabetes mellitus: a meta-analysis.

Patients with diabetes mellitus are at increased risk of developing atherosclerotic disease. The extent of this additional risk and its determinants are not well known, but this information is needed for sample-size estimations in intervention studies. Therefore, a meta-analysis of epidemiologic studies on this subject was performed. Medline was searched from 1966 onwards, including the reference lists of all relevant publications. A total of 27 prospective follow-up studies in the English language that allowed calculation of the unadjusted incidence of one of the predefined outcome events were included. The influence of age, sex, type of diabetes, duration of diabetes, year of study, HbA1c, cholesterol level, blood pressure and smoking on these incidences was studied by means of univariate Poisson regression analysis. Overall total mortality was 2.9% per year (95% CI 2.8-3.0; 27 studies), and for death from all vascular causes was 1.4% per year (95% CI 1.3-1.4; 16 studies). Only two studies were found that reported on the incidence of the composite outcome 'event death from all vascular causes, non-fatal myocardial infarction, or non-fatal stroke'. In univariate analysis, age, year of study, total cholesterol and systolic blood pressure were positively related to total mortality and death from all vascular causes. After adjustment for age, or limiting the analyses to studies in patients with type 2 diabetes only (n = 11), these relationships remained statistically significant. In conclusion, the overall yearly total mortality in diabetes mellitus is 2.9% and for death from all vascular causes is 1.4%. There are few data on the incidence of composite cardiovascular outcome events.

Desktop Agent Manager (DAM): Decision Mechanism

Desktop software agents are background processes that notify a computer user of certain predefined events. The complexity of desktop computing is increasing due to the proliferation of software agents. A desktop agent manager (DAM) may become an important component of desktop computing. This article focuses on the decision mechanism for the DAM to decide which agents should be allowed to access the user, which agents' results should be stored for future review by the user, and which of agents should be filtered out. We prove the validity of the concept of a DAM by developing an architecture that includes both a prototype of the DAM and a simulator of various types of agents. In this article, we present the results of our simulations and analyses of the DAM decision mechanism.

Knowledge-based multimedia information retrieval in hyperspace

In this paper, we propose a Smart WWW Page model, in which a smart WWW page is defined as a Web page with associated knowledge. Associated knowledge enables a smart WWW page to react to the occurrence of pre-defined events and perform appropriate actions. Therefore, the smart WWW pages can behave in an active way. This overcomes a WWW page's passive nature which constraints transactions between a WWW client system and its user. Since active index can describe knowledge and is a powerful computing device, it is thus applied to this proposed model. There are various WWW-based applications of this model. One is to improve the efficiency of on-line information retrieval in hyperspace by prefetching. A prototype of a knowledge-based WWW client system, named Mosaic-IC, has been developed by the authors. Experiment results show that a greater retrieval and navigation efficiency can be obtained by this knowledge-based WWW client system.

Development of the On-Line Operator Aid System OASYS Using A Rule-Based Expert System and Fuzzy Logic for Nuclear Power Plants

The On-line Operator Aid SYStem (OASYS) has been developed to support the operator`s decision making process and to ensure the safety of a nuclear power plant by providing operators with proper guidelines in a timely manner, according to the plant operation mode. The OASYS consists of four systems such as a signal validation and management system (SVMS), a plant monitoring system (PMS), an alarm filtering and diagnostic system (AFDS), and a dynamic emergency procedure tracking system (DEPTS). The SVMS and the PMS help operators to maintain a plant in a condition to withstand the adverse events during a normal operation condition. The AFDS covers the abnormal events until it exceeds the limit range of reactor trip signals, while after a reactor trip, the DEPTS aids operators with proper guidelines so as to shut down safely. The OASYS uses a rule-based expert system and fuzzy logic. The rule-based expert system is used to classify the predefined events and track the emergency operating procedures (EOPs) through data processing, and the fuzzy logic is used to generate the conceptual high-level alarms for the prognostic diagnosis and to evaluate the qualitative fuzzy criteria used in the EOPs. Evaluation results show that the OASYS ismore » capable of diagnosing plant abnormal conditions and providing operators appropriate guidelines with fast response time and consistency. The proposed system is implemented on a SUN-4/75 workstation using C language and Quintus prolog language. Currently, the OASYS is installed in the real-time full scope simulator for validation.« less

Snoop: An expressive event specification language for active databases

Making a database system active to meet the requirements of a wide range of applications entails developing an expressive event specification language and its implementation. Extant systems support mostly database events and in some cases a few predefined events. This paper discusses an event specification language (termed Snoop) for active databases. We define an event, distinguish between events and conditions, classify events into a class hierarchy, identify primitive events, and introduce a small number of event operators for constructing composite (or complex) events. Snoop supports temporal, explicit, and composite events in addition to the traditional database events. The novel aspect of our work lies not only in supporting a rich set of events and event expressions, but also in the notion of parameter contexts. Essentially, parameter contexts augment the semantics of composite events for computing their parameters. For concreteness, we present parameter computation for the relational model. Finally, we show how a contingency plan that includes time constraints can be supported without stepping outside of the framework proposed in this paper.