Optimal and practical handover decision algorithms in heteregeneous marco-femto cellular networks

Driven by the smart tablet/phone revolution and the proliferation of bandwidth hungry applications such as cloud computing and streaming video, the demand for high data rate wireless communication is increasing tremendously. In order to meet the increasing demand from subscribers, wireless operators are in the process of augmenting their macrocell network with supplemental infrastructure such as microcells, distributed antennas and relays. An alternative with lower upfront costs is to improve indoor coverage and capacity by using end-consumer installed femtocells. A femtocell is a low power, short range (up to 100 meters coverage radius) cellular wireless access point (AP), functioning in service provider owned licensed spectrum. Due to the proximity of end users to the femtocell access points, APs are able to provide higher end-user QoE and better spatial reuse of limited spectrum. Femtocells are useful in offloading the macro-cellular network as well as reducing the operating and capital expenditure costs for operators. Femtocells coexist with legacy cellular networks consisting of macrocells. In this emerging combined architecture, large number of Femtocell Application Point (FAPs) is randomly deployed in the coverage area of macro BSs. However, several problems related to MM (mobility management) and RM (resource management) in this combined architecture still remain to be solved. The ad hoc deployment of FAPs and asymmetric radio communication and call processing capabilities between macrofemto networks are the primary causes of these problems. Uncoordinated deployment of FAPs providing indoor oriented wireless access service within the macro coverage may cause severe interference problems that need to be mitigated and handled by RM/MM schemes. The MM decisions should take into account the resource constraints and UE mobility in order to prevent unnecessary or undesirable handovers towards femtocells. Ignoring these factors in MM decisions may lead to low customer satisfaction due to mismanagement of handover events in the combined macro-femto network, delayed signaling traffic and unsatisfactory call/connection quality. In order to address all of the aforementioned issues, the handover decision problem in combined femto-macro networks has been formulated as a multi-objective non-linear optimization problem. Since there are no known analytical solution to this problem, an MDP (Markov Decision Process) based heuristic has been proposed as a practical and optimal HO (handover) decision making scheme. This heuristic has been updated and improved in an iterative manner and has also been supported by a dynamic SON (Self Organizing Networks) algorithms that is based on heuristic's components. The performance results show that the final version of MDP based heuristic has signi cantly superior performance in terms offloading the macro network, minimizing the undesirable network events (e.g. outage and admission rejection) when compared to state-of-art handover algorithms

Accurate non-intrusive residual bandwidth estimation in WMNs

The multi-access scheme of 802.11 wireless networks imposes difficulties in achieving predictable service quality in multi-hop networks. In such networks, the residual capacity of wireless links should be estimated for resource allocation services such as flow admission control. In this paper, we propose an accurate and non-intrusive method to estimate the residual bandwidth of an 802.11 link. Inputs from neighboring network activity measurements and from a basic collision detection mechanism are fed to the analytical model so that the proposed algorithm calculates the maximum allowable traffic level for this link. We evaluate the efficiency of the method via OPNET simulations, and show that the percent estimation error is significantly lower than two other prominent estimation methods, bounded only between 2.5-7.5%. We also demonstrate that flow admission control is successfully achieved in a realistic WMN scenario. Flow control through our proposed algorithm keeps the unsatisfied traffic demand bounded and at a negligibly low level, which is less than an order of magnitude of the other two methods

Video yardımcılı torakal cerrahi sonrası postoperatif analjezi yönetimi için ultrasonografi rehberliğinde yapılan erektor spina plan bloğu ve torakal paravertebral blok etkinliği: Prospektif, randomize, kontrollü çalışma

Objective: Evaluation of the effectiveness of ultrasound (US)-guided erector spinae plane block (ESPB) and thoracic paravertebral block (TPVB) compared to no intervention control group for postoperative pain management in video assisted thoracic surgery (VATS) patients. Method: Three groups - Group ESPB, Group TPVB and the control group (n=30 per group) were included in this prospective, randomized, controlled study. The US-guided blocks were performed preoperatively in the ESPB and TPVB groups. Intravenous patient-controlled postoperative analgesia via fentanyl was administered in all of the patients. The patients were evaluated using visual analogue scale (VAS) scores, opioid consumption, and adverse events. Results: At all time intervals fentanyl consumption and VAS scores were significantly lower both in ESPB and TPVB groups compared to the control group (p<0.001). Block procedure time was significantly lower and success of one time puncture was higher in Group ESPB as compared with that in Group TPVB (p<0.001). Conclusion: ESPB and TPVB provide more effective analgesia compared to control group in patients who underwent video-assisted thoracic surgery. ESPB had a shorter procedural time and higher success of single-shot technique compared to TPVB.Amaç: Video yardımcılı torakal cerrahi yapılan hastalarda postoperatif analjezi yönetimi içinultrasonografi (US) eşliğinde yapılan erektor spina plan bloğu (ESPB) ve torakal paravertebralbloğun (TPVB) kontrol grubuna göre etkinliğinin değerlendirilmesi amaçlanmıştır.Yöntem: Bu çalışmaya her grup için 30 hasta olmak üzere toplam 90 hasta dahil edilmiştir.Çalışma 3 gruptan oluşmaktadır; Grup ESPB, Grup TPVB ve Kontrol Grubu. ESPB ve TPVB gruplarındaki hastalara preoperatif olarak US eşliğinde blok yapıldı. Tüm gruplardaki hastalara fentaniliçeren hasta kontrollü analjezi (HKA) uygulandı. Hastalar vizuel analog skala (VAS), opioid tüketimi ve yan etkiler kaydedilerek değerlendirildi.Bulgular: Tüm zaman aralıklarında fentanil tüketimi ve VAS Grup ESPB ve Grup TPVB de kontrolgrubuna göre anlamlı olarak daha düşüktü (p<0.001). Blok işlem süresi ESPB grubunda anlamlıolarak daha kısaydı ve iğne ile tek giriş başarısı ESPB grubunda TPVB grubuna göre anlamlı olarakdaha yüksekti (p<0.001).Sonuç: ESPB ve TPVB, video yardımcılı torakal cerrahi yapılan hastalarda kontrol grubuna göreetkili analjezi oluşturmaktadır. ESPB, TPVB’ye göre daha kısa işlem süresi ve tek iğne girişi ile dahayüksek başarı oranına sahiptir

16. gestasyonel haftada uygulanan kurtarıcı analjezi amaçlı erektör spina plan bloğu

The Journal of the Turkish Society of AlgologyNonobstetric operations are sometimes necessary during pregnancy, with an estimated incidence of about 2% among pregnant women. In recent years, laparoscopic procedures have been preferred for abdominal surgery in pregnancy, as these are well tolerated by both the mother and fetus during all trimesters of pregnancy. Postoperative pain management is important for pregnant patients undergoing a nonobstetric procedure, as pain may increase the risk of premature labor. For pain management during pregnancy, paracetamol is the drug of choice, and nonsteroidal anti-inflammatory drugs should be avoided. Regional blockade techniques are preferred, as they reduce the risk of opioidinduced hypoventilation

MDP based handover decision algorithm for femtocells (Femtocell şebekeleri için MKP temelli handover karar algoritması)

Femtocells emerge as an alternate solution meeting the ever-increasing demand for high wireless data rates in a cost effective way. Nevertheless, femtocells are also sharing the same licensed UMTS frequencies with macrocells and they are deployed by end-users in ad hoc manner. The mobility management in the resulting macro-femto combined network should be performed according to the characteristics of this asymmetric interaction. The presented study proposes an optimal MDP based handover decision mechanism that takes into account important interaction factors. Through simulations, the performance of the novel algorithm has been compared to the state-of-art methods. The results show that end-user QoS and the ratio of utilization for femtocell network increase in significant manner

Estimating the channel capacity of multi-hop IEEE 802.11 wireless networks

In IEEE802.11 wireless networks, the residual capacity of the wireless links should be accurately estimated to realize advanced network services such as flow admission control or load balancing. In this paper, we propose an algorithm that estimates the packet delivery failure probability by collecting transmission statistics from nearby nodes, and by using a basic collision detection mechanism. This probability is then used in an analytical model to calculate the maximum allowable traffic needed to reach the saturation condition. We show by simulations that estimation error is within 0.5-2.0%, which is significantly lower than the best performance of prior estimation methods. We also demonstrate that the flow admission control is successfully achieved in a realistic wireless network scenario by the help of accurate link residual bandwidth estimation, where the unsatisfied traffic demand remain bounded at a negligibly low level. A routing algorithm that finds max-min residual bandwidth path between source and destination nodes is also implemented, and simulation results show that the network throughput achieved by this algorithm significantly exceeds that of other popular mesh routing protocols. Finally, we provide test results from the real implementation of our algorithm on 802.11 wireless equipment, which are consistent with the simulations

ENERJİ YATIRIMLARINDA SOSYAL KABULÜ ETKİLEYEN FAKTÖRLERİN DEĞERLENDİRİLMESİ

Bu çalışmada, enerji yatırımlarında sosyal kabulü etkileyen faktörlerin değerlendirilmesi amaçlanmaktadır. Çalışmada İzmir Bornova ilçe merkezi evren olarak belirlenmiş, 18 yaş ve üzeri bireyler kapsama alınmıştır. Örneklem, basit rastgele örneklem seçim yöntemiyle belirlenen 236 kişiden oluşmuştur. Toplanan veriler SPSS 16,0 istatistik programı kullanılarak analiz edilmiş, veri çözümlenmesinde frekans dağılımı ve yüzdelerden yararlanılmış, değişkenler arasındaki farkın belirlenmesinde ki-kare testi kullanılmıştır. Yapılan çalışmada yenilenebilir enerji yatırımlarına yönelik sosyal kabul, konvansiyonel enerji üretim yatırımlarına göre daha yüksektir. En düşük sosyal kabul oranı nükleer enerji yatırımlarındayken, özellikle jeotermal yatırımlara karşı kabulün düşüklüğü dikkat çekicidir. Sosyal kabulde etkili faktörler olarak, yatırımın yaşam alanına uzaklığı, doğal çevreye, insan sağlına ve tarım alanlarına olumsuz etkileri belirleyici olarak görülmektedir. Enerji yatırımlarında sosyal kabul, yatırımı engelleyici ya da geciktirici bir faktör olarak değerlendirilmemeli, tam tersi enerji yatırımlarında kamusal yararın sağlanması adına önemsenmesi gereken bir faktör olarak görülmelidir. Kamu idaresi tarafından katılım mekanizmalarının kolaylaştırılması ve etkin bilgilendirmenin sağlanması, enerji yatırımına karşı sosyal kabulün artmasına katkı sağlamaktadır

Efficacy of an ultrasound-guided erector spinae plane block for postoperative analgesia management after video-assisted thoracic surgery: A prospective randomized study

Objectives: Investigate whether an ultrasound-guided erector spinae plane block (ESPB) can be used to manage postoperative pain in video-assisted thoracic surgery (VATS) patients. Design: Prospective, randomized study. Setting: Single institution, academic university hospital. Participants: Adult patients who underwent VATS under general anesthesia between September 2018 and March 2019. Interventions: This study was an interventional study. Measurements and Main Results: A total of 60 patients were randomly assigned into 2 groups (n = 30 per group): an ESPB group and a control group. In the ESPB group, a single-shot ultrasound-guided ESPB was administered preoperatively. The control group received no such intervention. All of the patients received intravenous patient-controlled postoperative analgesia, and they were assessed using visual analogue scale (VAS) scores, opioid consumption, and adverse events. There were no statistically significant intergroup differences with respect to the age, sex, weight, American Society of Anesthesiologists status, anesthesia duration, and surgery length (p> 0.05 for each). The opioid consumption at 1, 2, 4, 8, 16, and 24 hours and the active and passive VAS scores at 0, 2, 4, 8, 16, and 24 hours were statistically lower in the ESPB group at all of the time periods when compared with the control group (p <0.05). In the control group, the nausea and itching rates were higher, but there were no intergroup differences in terms of other adverse effects. Conclusions: A preemptive single-shot ESPB may provide effective analgesia management after VATS

Comparison of ultrasound-guided type-II pectoral nerve block and rhomboid intercostal block for pain management following breast cancer surgery: A randomized, controlled trial

Purpose Although breast-conserving surgery-axillary dissection (BCS-AD) is a minimally invasive surgery, patients may suffer from moderate-to-severe pain. Several regional techniques can be used for pain control. The type II pectoral nerve block (PECS II) and the rhomboid intercostal block (RIB) are interfascial plane blocks that have been reported to provide effective analgesia after breast surgery. This study aims to compare the analgesic efficacy of the PECS II block and the RIB after breast surgery. Patients and Methods Ninety female patients aged 18 to 65 years with American Society of Anesthesiologists (ASA) classes I and II physical status who underwent unilateral BCS-AD surgery were included. Patients were divided into three groups (n = 30 in each): the PECS II group, the RIB group, or the control group. PECS II block and RIB were performed with 30 mL 0.25% bupivacaine. Ibuprofen 400 mg IV 3 x 1 was given in the postoperative period. A patient control analgesia device included a dose of 10 mu g/mL fentanyl, which was prepared and connected to the patients. Results There were no statistical differences between groups in terms of demographical data. Postoperative fentanyl consumption was significantly lower in the PECS II and RIB groups than the control group. The need for rescue analgesia use was significantly higher in the control group than the other groups. At all times, visual analog scale scores were significantly lower in the PECS II and RIB groups than the control group. Conclusions The PECS II block and the RIB provide similar effective analgesia after BCS-AD

Comparison of Ultrasound‐Guided Type‐II Pectoral Nerve Block and Rhomboid Intercostal Block for Pain Management Following Breast Cancer Surgery: A Randomized, Controlled Trial

Purpose Although breast-conserving surgery-axillary dissection (BCS-AD) is a minimally invasive surgery, patients may suffer from moderate-to-severe pain. Several regional techniques can be used for pain control. The type II pectoral nerve block (PECS II) and the rhomboid intercostal block (RIB) are interfascial plane blocks that have been reported to provide effective analgesia after breast surgery. This study aims to compare the analgesic efficacy of the PECS II block and the RIB after breast surgery. Patients and Methods Ninety female patients aged 18 to 65 years with American Society of Anesthesiologists (ASA) classes I and II physical status who underwent unilateral BCS-AD surgery were included. Patients were divided into three groups (n = 30 in each): the PECS II group, the RIB group, or the control group. PECS II block and RIB were performed with 30 mL 0.25% bupivacaine. Ibuprofen 400 mg IV 3 x 1 was given in the postoperative period. A patient control analgesia device included a dose of 10 mu g/mL fentanyl, which was prepared and connected to the patients. Results There were no statistical differences between groups in terms of demographical data. Postoperative fentanyl consumption was significantly lower in the PECS II and RIB groups than the control group. The need for rescue analgesia use was significantly higher in the control group than the other groups. At all times, visual analog scale scores were significantly lower in the PECS II and RIB groups than the control group. Conclusions The PECS II block and the RIB provide similar effective analgesia after BCS-AD