Bariatric and metabolic surgeries have gained extensive popularity and trust due to their documented efficacy and safety in managing not only obesity but also associated comorbidities such as diabetes mellitus, hypert...Bariatric and metabolic surgeries have gained extensive popularity and trust due to their documented efficacy and safety in managing not only obesity but also associated comorbidities such as diabetes mellitus, hypertension, dyslipidemia, sleep apnea, and joint pain. Traditionally, bariatric surgeries have been categorized into hypoabsorptive, restrictive, or hybrid approaches. However, these classifications inadequately reflect the complex anatomical and physiological alterations associated with modern surgical methodologies. This paper explores the evolution of metabolic surgeries, emphasizing the integration of physiological concepts into classic procedures to provide more tailored and effective treatment options for obesity and its comorbidities. Finally, the proposal for a new classification based on current metabolic concepts will facilitate communication among patients, doctors, and healthcare professionals. Additionally, it will enable a more didactic and standardized approach to data collection for conducting studies and publications.展开更多
The scarcity of bandwidth in the radio spectrum has become more vital since the demand for more and more wireless applications has increased. Most of the spectrum bands have been allocated although many studies have s...The scarcity of bandwidth in the radio spectrum has become more vital since the demand for more and more wireless applications has increased. Most of the spectrum bands have been allocated although many studies have shown that these bands are significantly underutilized most of the time. The problem of unavailability of spectrum and inefficiency in its utilization has been smartly addressed by the cognitive radio （CR） technology which is an opportunistic network that senses the environment, observes the network changes, and then uses knowledge gained from the prior interaction with the network to make intelligent decisions by dynamically adapting their transmission characteristics. In this paper, some of the decentralized adaptive medium access control （MAC） protocols for CR networks have been critically analyzed, and a novel adaptive MAC protocol for CR networks, decentralized non-global MAC （DNG-MAC）, has been proposed. The results show the DNG-MAC outperforms other CR-MAC protocols in terms of time and energy efficiency.展开更多
In multi-hop cognitive radio networks （ CRNs）, the heterogeneous environment increases the complexity of common control channel （CCC） formation and routing protocol design. In this paper, we consider the on-demand...In multi-hop cognitive radio networks （ CRNs）, the heterogeneous environment increases the complexity of common control channel （CCC） formation and routing protocol design. In this paper, we consider the on-demand routing protocol transmits over CCC. However, since CR transceivers （secondary users） have different available channel sets and it must vacate the licensed channel when a primary user arrives, forming a CCC becomes a main challenge in routing protocol design for CRNs. Our proposed CCC formation algorithm is based on a spectrum-tree structure, which consists of all cluster heads in CRNs. The cluster heads are with smaller moving range and lower mobility, and also act as a router in the whole network which maintains information of its cluster. Hence, a route is constituted in part by a set of cluster-head identity （ID） numbers, which represent the spe- cific cluster heads the path traverses, and in part by a set of member nodes ID numbers, which are included in the clusters containing the source and destination nodes. Due to high mobility and dynamic available spectrum, we define the stability parameters of path as two parts. One stability parameter is mobility factor, which represents the probability that a pairwise node can keep in communication range for the next flow transmission. The another stability parameter is spectrum opportunistic （SOP） factor, which represents the probability that a pairwise links can obtain the assigned spectrum band for the next flow transmission. Simulation results show that CCC formation algorithm produces a high probability of CCC formation, and the proposed routing protocol performs better than typical routing protocols.展开更多
The choledochal cyst(CC)can be better termed as biliary tract malformation because of the close association of embryology and etiology in the causation of CC.Contrary to Babbitt's postulation of reflux,damage and ...The choledochal cyst(CC)can be better termed as biliary tract malformation because of the close association of embryology and etiology in the causation of CC.Contrary to Babbitt's postulation of reflux,damage and dilatation,reflux was not demonstrable as the causative factor in all varieties of CC.High pressure in the biliary system,otherwise termed ductal hypertension,is put forth as an alternative to explain the evolution of CC.The forme fruste type,which does not find a place in the standard classification,typifies the ductal hypertension hypothesis.Hence a closer,in-depth review would be able to highlight this apt terminology of biliary tract malformation.展开更多
Embedding specific signatures in transmitted signals for identifying common control channels of cognitive radio are addressed in research laboratories because availability of the spectrum occupied by the common contro...Embedding specific signatures in transmitted signals for identifying common control channels of cognitive radio are addressed in research laboratories because availability of the spectrum occupied by the common control channel might change in time.A novel solution to embed a unique cyclostationary signature for the common control channel of cognitive radio is proposed in this article.Based on linear periodically time-variant transformation(LPTV)model,the cyclic autocorrelation expression of the proposed signature is derived,which characterizes its cyclostationarity.Analysis of the cyclostationary signature is presented considering effects of additive white Gaussian noise(AWGN)and multiplath channels.Simulation results illustrating the reliability of signatures are given.展开更多
文摘Bariatric and metabolic surgeries have gained extensive popularity and trust due to their documented efficacy and safety in managing not only obesity but also associated comorbidities such as diabetes mellitus, hypertension, dyslipidemia, sleep apnea, and joint pain. Traditionally, bariatric surgeries have been categorized into hypoabsorptive, restrictive, or hybrid approaches. However, these classifications inadequately reflect the complex anatomical and physiological alterations associated with modern surgical methodologies. This paper explores the evolution of metabolic surgeries, emphasizing the integration of physiological concepts into classic procedures to provide more tailored and effective treatment options for obesity and its comorbidities. Finally, the proposal for a new classification based on current metabolic concepts will facilitate communication among patients, doctors, and healthcare professionals. Additionally, it will enable a more didactic and standardized approach to data collection for conducting studies and publications.
文摘The scarcity of bandwidth in the radio spectrum has become more vital since the demand for more and more wireless applications has increased. Most of the spectrum bands have been allocated although many studies have shown that these bands are significantly underutilized most of the time. The problem of unavailability of spectrum and inefficiency in its utilization has been smartly addressed by the cognitive radio （CR） technology which is an opportunistic network that senses the environment, observes the network changes, and then uses knowledge gained from the prior interaction with the network to make intelligent decisions by dynamically adapting their transmission characteristics. In this paper, some of the decentralized adaptive medium access control （MAC） protocols for CR networks have been critically analyzed, and a novel adaptive MAC protocol for CR networks, decentralized non-global MAC （DNG-MAC）, has been proposed. The results show the DNG-MAC outperforms other CR-MAC protocols in terms of time and energy efficiency.
文摘In multi-hop cognitive radio networks （ CRNs）, the heterogeneous environment increases the complexity of common control channel （CCC） formation and routing protocol design. In this paper, we consider the on-demand routing protocol transmits over CCC. However, since CR transceivers （secondary users） have different available channel sets and it must vacate the licensed channel when a primary user arrives, forming a CCC becomes a main challenge in routing protocol design for CRNs. Our proposed CCC formation algorithm is based on a spectrum-tree structure, which consists of all cluster heads in CRNs. The cluster heads are with smaller moving range and lower mobility, and also act as a router in the whole network which maintains information of its cluster. Hence, a route is constituted in part by a set of cluster-head identity （ID） numbers, which represent the spe- cific cluster heads the path traverses, and in part by a set of member nodes ID numbers, which are included in the clusters containing the source and destination nodes. Due to high mobility and dynamic available spectrum, we define the stability parameters of path as two parts. One stability parameter is mobility factor, which represents the probability that a pairwise node can keep in communication range for the next flow transmission. The another stability parameter is spectrum opportunistic （SOP） factor, which represents the probability that a pairwise links can obtain the assigned spectrum band for the next flow transmission. Simulation results show that CCC formation algorithm produces a high probability of CCC formation, and the proposed routing protocol performs better than typical routing protocols.
文摘The choledochal cyst(CC)can be better termed as biliary tract malformation because of the close association of embryology and etiology in the causation of CC.Contrary to Babbitt's postulation of reflux,damage and dilatation,reflux was not demonstrable as the causative factor in all varieties of CC.High pressure in the biliary system,otherwise termed ductal hypertension,is put forth as an alternative to explain the evolution of CC.The forme fruste type,which does not find a place in the standard classification,typifies the ductal hypertension hypothesis.Hence a closer,in-depth review would be able to highlight this apt terminology of biliary tract malformation.
基金supported by Nokia Device R&D China,the National Basic Research Program of China(2007CB310602)
文摘Embedding specific signatures in transmitted signals for identifying common control channels of cognitive radio are addressed in research laboratories because availability of the spectrum occupied by the common control channel might change in time.A novel solution to embed a unique cyclostationary signature for the common control channel of cognitive radio is proposed in this article.Based on linear periodically time-variant transformation(LPTV)model,the cyclic autocorrelation expression of the proposed signature is derived,which characterizes its cyclostationarity.Analysis of the cyclostationary signature is presented considering effects of additive white Gaussian noise(AWGN)and multiplath channels.Simulation results illustrating the reliability of signatures are given.
