958 research outputs found
Using Hidden Markov Model for Stock Day Trade Forecasting
Around the world, the Hidden Markov Models (HMM) are the most popular methods in the machine learning and statistics for modeling sequences, especially in speech recognition domain. According to the number of patent applications for speech recognition technology form 1988 to 1998, the trend shows that this method has become very mature. In this thesis, we will make a new use of the HMM and apply it on day trading stock forecast.
However, the HMM is based on probability and statistics theory. In a statistics framework, the HMM is a composition of two stochastic processes, a Hidden Markov chain, which accounts for temporal variability, and an observable process, which accounts for spectral variability. The combination contains uncertainly status just likes the stock walk trace. Therefore, the HMM and the stock walk trace have the same idea by coincidence. In this thesis, we will try to learn the stock syntax; just like how the HMM model was used in speech recognition in different languages, and the take the next step ahead in price prediction.
Additionally, the stock market is the reflection of the economy. The stock trace is impacted by many factors such as policy, psychology, microeconomics, economics, and capital, etc. There, in this thesis, the TAIFEX Taiwan index futures (TX) and day trade are used to avoid all the uncertainty factors. After the all experiments, it is proven that the HMM is better than the benchmark methodRandom Walk method and the Investment Trust & Consulting Association method- Modified Trading method. Moreover, the result is very conspicuous by the statistics testing of significance
Bridge scour evaluation based on ambient vibration
The vulnerability of bridges to hazards such as earthquakes, wind and floods necessitates special structural characteristics. To guarantee the stability of bridge structures, the precise evaluation of the scour depth of bridge foundation has recently become an important issue, as most of the unexpected damage to or collapse of bridges has been attributed to hydraulic issues. In this paper, a vibration-based bridge health monitoring system that utilizes only the response of superstructure to rapidly evaluate the embedded depth of a bridge column is proposed. To clarify the complex fluid-solid coupling phenomenon, the effects of embedded depth and water level were first verified through a series of static experiments. A confined finite element model simulated by soil spring effects was then established to illustrate the relationship between the fundamental frequency and the embedded depth. Using the proposed algorithm, the health of the bridge is able to be inferred by processing the ambient vibration response of the superstructure. To implement the proposed algorithm, a SHM prototype system monitoring environmental factors such as temperature, water level, and inclination was developed to support on-line processing. The performance of the proposed system was verified by a series of dynamic bridge scour experiments conducted in a laboratory flume and compared with readings from a water-proof camera. The results showed that using the proposed vibration-based bridge health monitoring system, the embedded depth of bridge column during complex scour processes is able to be reliably calculated
Endoscopic Balloon Dilatation for Esophageal Strictures in Children Younger Than 6 Years: Experience in a Medical Center
Esophageal strictures in children may be caused by congenital anomaly, caustic agent or foreign body ingestion, complication of reflux esophagitis, and after esophageal surgery. Accidental ingestion of alkaline fluid is the most common cause of corrosive esophagitis in children in Taiwan. In this article, we studied 10 pediatric patients who had esophageal strictures and required endoscopic balloon dilatation (EBD) therapy under general anesthesia from January 2003 to June 2009. The median age of the studied children who received their first EBD treatment was 36.2 months (13.4–60.9 months), with a dilator size of 8.0mm (5–12 mm). The interval between injury and initial EBD was 3.0 months (1.3–60.8 months). The treatment duration averaged 16.7 months (3.0–69.3 months), with 13.5 (4–31) instances of EBD therapy per patient. The greater the length of stricture, the more number of times EBD was needed. In these cases, no severe complication was found after the procedure. The result indicated that EBD under general anesthesia was a safe and effective method to resolve the symptom of dysphagia and diet condition. Because of the limited number of study cases, long-term studies are required to further confirm the clinical effect of EBD under general anesthesia
Differential functional genomic effects of anti-inflammatory phytocompounds on immune signaling
Ankle-Brachial Index Is a Powerful Predictor of Renal Outcome and Cardiovascular Events in Patients with Chronic Kidney Disease
Ankle-brachial index (ABI) is an accurate tool to diagnose peripheral arterial disease. The aim of this study was to evaluate whether ABI is also a good predictor of renal outcome and cardiovascular events in patients with chronic kidney disease (CKD). We enrolled 436 patients with stage 3–5 CKD who had not been undergoing dialysis. Patients were stratified into two groups according to the ABI value with a cut point of 0.9. The composite renal outcome, including doubling of serum creatinine level and commencement of dialysis, and the incidence of cardiovascular events were compared between the two groups. After a median follow-up period of 13 months, the lower ABI group had a poorer composite renal outcome (OR = 2.719, P = 0.015) and a higher incidence of cardiovascular events (OR = 3.260, P = 0.001). Our findings illustrated that ABI is a powerful predictor of cardiovascular events and renal outcome in patients with CKD
Hemispheric dispersion of radioactive plume laced with fission nuclides from the Fukushima nuclear event
Radioactivities of particulate 131I and 137Cs released from the Fukushima nuclear accident were monitored in a regional aerosol network including two high mountain sites (central Taiwan and Tibetan Plateau). The results were integrated with data measured elsewhere around the world, with special focus on the mid-latitudes. The hemispheric transport of the Fukushima radiation clouds (FRCs) by the westerlies took 3–4 km, whereas the second one up to 5 km or more. 131I and 137Cs were fractionated during transport, with 137Cs concentrated in the shallower layer, susceptible to depositional removal, while 131I moving faster and higher. This accident may be exemplified to identify some atmospheric processes on the hemispheric scale
New primers for methylation-specific polymerase chain reaction enhance specificity of detecting STAT1 methylation
AbstractObjectiveSignal transducer and activator of transcription (STAT)1 is a key tumor suppressor, which is always methylated in a variety of human cancers. However, nonspecific primers for the detection of specific promoter hypermethylation of STAT1 gene can lead to false-positive or false-negative results for gene methylation.Materials and MethodsWe designed new primers for the detection of STAT1 methylation and compared the sensitivities and specificities of these new primers with prior published primers by methylation-specific polymerase chain reaction (PCR) from ovarian clear cell carcinomas. The mRNA expression levels of STAT1 in these cancerous tissues were also evaluated by reverse-transcriptase PCR and correlated with the results of promoter methylation of STAT1 gene.ResultsNine (39%) of the 23 samples detected by the new primers and 13 samples (56%) detected by prior published primers showed STAT1 methylation. A direct DNA sequencing test revealed that four of the 13 samples (30.8%) showed false positivity for STAT1 methylation using the prior published primers. In contrast, none of the nine samples was false-positive for the detection of STAT1 methylation using the new primers. The new primers for the detection of STAT1 methylation showed 100% specificity and 100% sensitivity without false positivity.ConclusionSpecific primers for methylation-specific PCR are mandatory for the accurate detection of STAT1 gene methylation. Besides, specific primers can generate correct interpretation of STAT1 gene methylation, and its correlation with the clinicopathological characteristics and outcome of cancer patients
Reconstruction for Mandibular Implant Failure
Mandibular defects may result from tumor ablations, trauma, or radiation necrosis. Significant segmental mandibular loss or hemimandibular loss may sometimes be replaced with mandibular implants by ENT surgeons/oral surgeons/head and neck surgeons. However, this may bring about mandibular implant failure in long-term follow-up. Mandibular implant failures usually manifest as: soft tissue atrophy, mandibular implant extrusion, infection, facial nerve involvement, facial asymmetry, derangement of occlusion and mastication, orocutaneous fistula, etc. Over 30 years, the authors have treated 102 patients with mandibular implant failure. Reconstruction may involve removal of the mandibular implant and immediate replacement of the mandibular defect with a piece of vascularized bone flap, not only to compensate for bone loss but also to replace neighboring soft tissue and possible skin defects. Frequently used flaps have been vascularized iliac bone (89/102) or vascularized fibula grafts (13/102). During follow-up, iliac bone flap reconstruction has yielded more favorable results due to its ample bone bulk and adequate soft tissue coverage. Fibula flaps with osteotomies have been associated with an increasing incidence of malunion/nonunion and subsequent easy deformation
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