647 research outputs found
Automatic sleep staging in obstructive sleep apnea patients using photoplethysmography, heart rate variability signal and machine learning techniques
No full textIt is extremely significant to identify sleep stages accurately in the diagnosis of obstructive sleep apnea. In the study, it was aimed at determining sleep and wakefulness using a practical and applicable method. For this purpose , the signal of heart rate variability (HRV) has been derived from photoplethysmography (PPG). Feature extraction has been made from PPG and HRV signals. Afterward, the features, which will represent sleep and wakefulness in the best possible way, have been selected using F-score feature selection method. The selected features were classified with k-nearest neighbors classification algorithm and support vector machines. According to the results of the classification, the classification accuracy rate was found to be 73.36 %, sensivity 0.81, and specificity 0.77. Examining the performance of the classification, classifier kappa value was obtained as 0.59, area under an receiver operating characteristic value as 0.79, tenfold cross-validation as 77.35 %, and F-measurement value as 0.79. According to the results accomplished, it was concluded that PPG and HRV signals could be used for sleep staging process. It is a great advantage that PPG signal can be measured more practically compared to the other sleep staging signals used in the literature. Improving the systems, in which these signals will be used, will make diagnosis methods more practical
Social media marketing: Example of instagram
No full textSosyal medyanın, hem bireysel hem de kurumsal kullanıcıları bulunmaktadır. Firmaların, sosyal medya hesaplarını yönetmesi için personel istihdam etmeye başlamasıyla, sosyal medya uzmanlığı olarak yeni bir iş kolu ortaya çıkmıştır. Popüler bir sosyal medya platformu olan İnstagram'ı, kültür ve yaşam biçimi farklı olan her kesimden insan kullanabilmektedir. Bu çalışmanın amacı, İnstagram'ın üniversite öğrencileri tarafından ne amaçla kullanıldığını ve İnstagram'da satış yapan firmalara karşı tüketici davranışını tespit etmektir. Recep Tayyip Erdoğan Üniversitesi, İktisadi ve İdari Bilimler Fakültesi'nde öğrenim gören 390 öğrenciye anket uygulanmıştır. Katılımcıların kişisel bilgileri, İnstagram kullanım amaçları ve İnstagram'dan alışveriş yapma durumu tespit edildikten sonra, araştırma hipotezlerine yönelik analizler yapılmıştır. Analizlerde Pearson Chi-Square Testi kullanılmış olup, anlamlı ilişki tespit edildiğinde, ikili karşılaştırmalarda Bonferroni Testi kullanılmıştır. Elde edilen sonuçlara göre, öğrencilerin İnstagram kullanım amaçları sırasıyla, arkadaş takibi, fotoğraf ve video paylaşımı, alışveriş yapmak, modayı ve ünlüleri takip etmektir. Modayı takip etmek, alışveriş yapmak ve firmaları takip etmek için İnstagram'ı kullanan ve yaş olarak daha büyük olan kadın katılımcılar, İnstagram üzerinden daha çok alışveriş yapmaktadır.Social media has both individual and corporate users. As companies started to employ staff to manage their social media accounts, a new business line emerged as a social media expert. Instagram, a popular social media platform, can be used by people from all walks of life with different cultures and lifestyles. The aim of this study is to determine the use of Instagram by university students and consumer behavior towards companies selling on Instagram. A questionnaire was applied to 390 students studying at the Faculty of Economics and Administrative Sciences of Recep Tayyip Erdogan University. After identifying the participants' personal information, the use of Instagram and the status of shopping from Instagram, analyzes were conducted for the research hypotheses. Pearson Chi-Square Test was used in the analysis. According to the results, the purpose of Instagram usage is to follow friends, share photos and videos, shop, follow fashion and celebrities respectively. Female participants who use Instagram to follow fashion, shop and follow companies do more shopping on Instagram
Satisfaction and ethnocentrism levels of consumers for American brands
No full textBu çalışmanın amacı, tüketicilerin kullandıkları Amerikan markalarına yönelik memnuniyet ve etnosentrizm düzeyleri arasındaki ilişkinin ölçülmesi ve demografik özelliklerin etkisinin saptanmasıdır. Bu doğrultuda oluşturulan anket, Rize'de Recep Tayyip Erdoğan Üniversitesi, İktisadi ve İdari Bilimler Fakültesi'nde öğrenim gören ve kolayda örnekleme yöntemi ile seçilen 450 adet öğrenciye uygulanmıştır. Eksik veya hatalı cevaplanan 85 anket analize dahil edilmeyip kalan 365 anket analize tabi tutulmuştur. Katılımcıların etnosentrizm düzeylerini ölçmek için CETSCALE kullanılmıştır. Elde edilen verilerin analizi SPSS programı ile yapılmıştır. Frekans ve güvenilirlik analizleri uygulandıktan sonra bağımsız örneklem t testi, tek yönlü anova ve korelasyon analizleri yapılmıştır. Elde edilen sonuçlara göre ankete katılan öğrencilerin Amerikan markalarından yüksek düzeyde memnun oldukları ve bu markalara yönelik düşük etnosentrizm sergiledikleri tespit edilmiştir. Katılımcıların yaşı arttıkça Amerikan markalarına olan memnuniyet düzeyi azalmaktadır. Gelir düzeyi düştükçe, etnosentrizm düzeyi artmaktadır. Ayrıca Maliye Bölümü'nde öğrenim gören öğrencilerin, etnosentrizm düzeyinin diğer bölümlerde öğrenim gören öğrencilere kıyasla daha yüksek olduğu tespit edilmiştir.The purpose of this study is to measure the relationship between the satisfaction and ethnocentrism levels of Turkish consumers towards American brands and to determine the effect of demographic factors. A questionnaire was applied to 450 students studying at Recep Tayyip Erdogan University, Faculty of Economics and Administrative Sciences in Rize/Turkey by convenience sampling method. Questionnaires that were answered incomplete or incorrectly were not included in the analysis. Therefore the remaining 365 questionnaires were analyzed. CETSCALE was used to measure the ethnocentrism levels of the participants. The analysis of the data obtained was made by the SPSS program. After applying frequency and reliability analysis, independent sample t test, oneway Anova and correlation analyzes were performed. According to the results, the students participating in the survey were found to be highly satisfied with American brands and that they displayed low ethnocentrism for these brands. As the age of the participants increases, the level of satisfaction with American brands decreases. As the income level decreases, the level of ethnocentrism increases. In addition, students who study Finance have been found to have higher levels of ethnocentrism than students studying in other departments of the university
Planning and operation of dams
No full textHohai University, Jiangsu, China;China Society for Hydraulic Engineering, Beijing, China;China Society for Hydropower Engineering, Beijing, ChinaProceedings of the 4th International Conference on Dam Engineering - New Developments in Dam Engineering -- 18 October 2004 through 20 October 2004 -- Nanjing -- 64432The water discharged from a dam during operation must not cause floods downstream. Especially, if there is a large subcatchment area downstream and if surface runoff water due to rainfall cannot to be controlled, there is a considerable risk of flood downstream. Under these circumstances, the additive water coming from the reservoir will cause an increase in the flood damages. In this paper, the flood risks of rainfall water discharge from the subcatchment area, which is located in the downstream area of a dam and not completely controlled have been investigated. For this purpose, the decision matrix achieved from the rainfall of subcatchment, which lies between the Porsuk dam and Eskişehir city, was examined by taking the Porsuk subcatchment as a basi
Signal Processing and Communications Applications Conference
No full textObstructive Sleep Apnea Syndrome is one of the major diseases of our century. Diagnosis of this disease is very difficult. The reason of the difficulty is the complexity of the system. AHI index is calculated for the diagnosis of the disease as a result of respiratory scoring process. However it is necessary to use four different signals to do this operation. The reduction of signal measurements that discomforts the patient or using different signal measurements will provide the patient to sleep closer to his/her natural sleep environment which will increase the accuracy rate of the studies that are made in literature. Changes occurring in photoplethysmography signal during respiratory events were examined. In this study, the patient data that was used respiratory events were scored Changes on the photoplethysmography signals were examined. The data that were used in this study were respiratory events tagged apnea and hypopnea. For control, the photoplethysmography signals were recorded during normal breathing in sleep. The data were analyzed using the one-way analysis of variance method. According to the obtained results, the photoplethysmography signals have significant changes in between the apnea-hypopnea classes and normal classes during respiratory pauses in sleep. However, there are not significant differences between apnea and hypopnea classes. The study concluded that, in the scoring of respiratory events, photoplethysmography could be used more efficiently using a computer software
Alternatively New Signal for Sleep Staging Processing in Patients with Obstructive Sleep Apnea: Photoplethysmography Signal
No full textDiagnosis of Obstructive Sleep Apnea is done by expert doctors by examining biological signals which is obtain from the patient help of polysomnography device. Review, consists of two stages which are sleep staging and respiratory scoring. Sleep staging is done using Electroencephalogram, Electromyogram and Electrooculogram signals. Derivation of signal format gives discomfort to the patient. In order to connect the electrodes to the patient, there is a need expert technicians. In addition, the system is not suitable for use at home. When considering all these disadvantages, practical system is needed to make sleep staging. In this study, Photoplethysmography signal use will be suggested for alternative to the signals used in sleep staging process. Photoplethysmography signal can measure through the skin of any part of the body with noninvasive method. In the study, the characteristic features of Photoplethysmography signals were analyzed whether it is distinctive for sleep and wake statistically by means of Mann-Whitney U Test. According to the results obtained p < 0.05 and all properties are meaningful for sleep-wake. All features can be used as distinctive for the sleep-wakefulness are considered and also a practical sleep staging system be realized using Photoplethysmography signal
Signal Processing and Communications Applications Conference
No full textObstructive Sleep Apnea is a disease that occurs due to respiratory arrest in sleep. The diagnosis of the disease is made with the polysomnography device, which is the gold standard method of diagnosis. Diagnosis is performed by sleep staging and respiratory scoring steps. Respiratory scoring is performed with at least four signals. Technical knowledge is required to connect the electrodes. Moreover, the electrodes are so disturbing that it will delay the patient's sleeping time. Alternative systems for polysomnography devices are needed to solve these problems. In the study, Heart Rate Variable (HRV) derived from the photoplethysmographic signal was proposed for respiratory scoring. For the study, 15 features were extracted from HRV. Mann-Whitney U Test was used to determine whether the extracted features were distinguishing for apnea and control groups. According to the results, p < 0.05 belongs to properties 1-9 and 13-15, and these properties were found to be distinctive for the groups. According to the results of the study, respiratory scoring can be performed more practically by using HRV
A New Approach For Treatment of Chronic Obstructive Pulmonary Disease
No full textChronic Obstructive Pulmonary Disease (COPD) is a persistent respiratory disease usually caused by toxic gases. The diagnosis is made by a specialist doctor on a report taken by a specialist technician using a spirometer. Diagnostic steps can only be carried out in hospital environment in the presence of a qualified technician. The diagnostic process is so troublesome that it leads to alternative system requirements. In this study, a portable software system based on photoplethysmography signal is proposed as an alternative method to reduce the burden of the diagnosis process of the disease. For this purpose, 26 features were extracted from the photoplethysmography signal in time domain. The extracted features were classified by machine learning based k - Nearest Neighbors algorithm and tried to diagnose the disease. The study included 8 patients with COPD and a control group of 6 patients. Parameters such as accuracy, sensitivity, specificity and f-metric were used to calculate the classification performance. According to some k values and distance algorithms, all data are correctly classified as % 100, with a sensitivity of 1, a specificity of 1 and a measurement of F of 1. Given the results of the study, it has come to the conclusion that machine learning-based COPD diagnosis can be done effectively and productively
Evaluation of the Relationship Between Chronic Obstructive Pulmonary Disease and Photoplethysmography Signal
No full textChronic Obstructive Pulmonary Disease is a common respiratory disease. The diagnosis of the disease is made by a specialist doctor according to the report given by the spirometer device, which is the gold standard method for diagnosis. This method can only be performed in hospitals with the help of a technician. However, monitoring of the disease after diagnosis is important to follow the damage that the disease inflicts on the body. That's why the portability of diagnostic systems is vital. As a solution to these problems, there is a need for a portable system alternative to the spirometer device. In the study, a photoplethysmographic signal was suggested for the diagnosis of the disease. In the study, feature extraction was performed on 26 time domain from the photoplethysmographic signal and these properties were analyzed by Mann-Whitney U Test. According to the results obtained, p < 0.05 for features 2-6, 10-21, 23, 26 and these features were found to be distinctive for the disease. According to the results of the study, it is thought that the photoplethysmography signal can be used in the diagnosis of Chronic Obstructive Pulmonary Disease
Sağlık Bilimlerinde Güncel Tartışmalar 6
No full textBütün Yayın Hakları Saklıdır Kaynak gösterilerek tanıtım için yapılacak kısa alıntılar dışında yayıncının ve editörün yazılı izni olmaksızın hiçbir yolla çoğaltılamaz. ISBN: 978-625-7799-66-9 1.Baskı 25 Aralık 2022 Sağlık Bilimlerinde Güncel Tartışmalar 6 Türkçe ve İngilizce yayın hakları Bilgin Kültür Sanat Yayın Dağıtım Pazarlama Ltd. Şti.’e aittir. Fikir ve sanat eserleri yasası gereğince yazılı izin alınmadan kısmen ya da tamamen alıntı yapılamaz, hiçbir şekilde kopya edilemez, çoğaltılamaz ve yayımlanamaz. Editörler Recep AKKAYA Birnur AKKAYA </p
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