Efficient Heuristics for Virtual Machine Migration in Data Centers

Live migration of virtual machines is one of the essential virtualization technologies which enables the consolidation and load balancing in cloud data centers without interrupting the services. Main goals for optimizing a single virtual machine live migration is to minimize migration time, transferred data and downtime. Planning multiple live migrations in a data center has an essential impact on feasibility of consolidation and quality of services during migrations, however, optimizing parallel VM migrations has been studies less. Minimizing makespan (total migration time) while reducing energy and service quality degradation caused by using datacenter resources for migrations, are the main objectives of the problem. One of the issues in planning multiple live migrations is to detect and consider migrations order dependency constraints and possible deadlocks caused by lack of enough free resources in servers during the process. In the literature, exact mathematical models are not scalable and heuristics are not optimal and they don't consider the quality of service and energy efficiency of migration process when resources are restricted. In this work we propose a heuristic algorithm for scheduling the migration of virtual machines in a data center in order to minimize makespan (total migration time) and solve the conflicts (deadlocks) caused by limitation of resources with minimum cost and quality degradation

Residents’ perceptions of geotourism in Qeshm Island UNESCO Global Geopark, Iran

While much scholarly attention has explored the impacts of tourism behaviour on a destination, little is known about the effects of geotourism activities on host communities. Geotourism is a type of tourism based on geological features. It has been variously defined as a tourism with a ‘geological’ or ‘geographical’ orientation. This study addresses this gap in the literature by exploring residents’ perceptions of the impacts of geotourism development in the Qeshm UNESCO Global Geopark in the Persian Gulf in Iran. Qeshm Geopark has a sensitive environment as well as a strict traditional culture and it receives about 3 million visitors annually. The objectives of this study are threefold. Firstly, to enrich the geotourism literature with an analysis of residents’ attitudes. Secondly, to determine the extent of the relationship between geotourism development in Qeshm Geopark and the impacts on local residents. Thirdly, to consider whether locals’ attitudes towards geotourism development in Qeshm Island change over time. A quantitative method is used to achieve this goal with a sample of 266 residents of Qeshm Island. The data is analysed using a Confirmatory Factor Analysis and Structural Equation Modelling techniques. This study identified four geotourism impact domains and examined the effect of each domains on overall residents’ attitudes toward geotourism development in Qeshm Island. Results indicated that the overall residents’ attitudes are closely associated with their perceptions of positive cultural impacts in Qeshm Island. There is also a positive significant relationship between adverse urban issues and the overall residents’ attitudes in Qeshm Island. However, the residents’ positive perceptions and attitudes are much greater than the negative ones. The results of this study will enhance the knowledge of residents’ attitudes towards future geotourism development in Qeshm Island. This will help to identify the current problems in planning and management and identify possible solutions for future geotourism development. It should also assist planners in the establishment of tourism development policies and strategies which are informed by residents’ concerns and issues. In addition, it should help them minimise any adverse impacts whilst enhancing the overall benefits associated with geotourism development. This study also hopes to build on scholarly knowledge about geotourism, an important and emerging field

High-resolution analysis of the initiation of deep convection forced by boundary-layer processes

The initiation of atmospheric convection is investigated using the synergy of different instruments. The impact of increased spatial data resolution on the detection of the initiation of deep convection is analysed, and a methodology is developed to determine the likelihood of deep convection over flat and complex terrains. Intensive Observation Periods (IOPs) are used from the Convective Storm Initiation Project (CSIP), and the Convective and Orographically-Induced Precipitation Study (COPS)

Patient Decision Making in Vestibular Schwannoma: A Survey of the Acoustic Neuroma Association.

Objective To assess the decision-making process of patients with vestibular schwannoma (VS). Study Design Patients with VS completed a voluntary survey over a 3-month period. Setting Surveys were distributed online through email, Facebook, and member website. Subjects and Methods All patients had a diagnosis of VS and were members of the Acoustic Neuroma Association (ANA). A total of 789 patients completed the online survey. Results Of the 789 participants, 474 (60%) cited physician recommendation as a significant influential factor in deciding treatment. In our sample, 629 (80%) saw multiple VS specialists and 410 (52%) sought second opinions within the same specialty. Of those who received multiple consults, 242 (59%) of patients reported receiving different opinions regarding treatment. Those undergoing observation spent significantly less time with the physician (41 minutes) compared to surgery (68 minutes) and radiation (60 minutes) patients ( P < .001). A total of 32 (4%) patients stated the physician alone made the decision for treatment, and 29 (4%) felt they did not understand all possible treatment options before final decision was made. Of the 414 patients who underwent surgery, 66 (16%) felt they were pressured by the surgeon to choose surgical treatment. Conclusion Deciding on a proper VS treatment for patients can be complicated and dependent on numerous clinical and individual factors. It is clear that many patients find it important to seek second opinions from other specialties. Moreover, second opinions within the same specialty are common, and the number of neurotologists consulted correlated with higher decision satisfaction

Tourism Carrying Capacity Assessment for Historical Sites - Isfahan Emam Mosque

Isfahan as cultural capital of Islamic world is the most important tourism destination in Middle East and a profitable economic sector in Iran. Naghsh-E Jahan Square (Emam Square) was certified as a World Heritage Site in 1979. Among the tourist sites in Naghsh-E Jahan Square, Emam mosque is a place which attracts the largest number of visitors. The unplanned tourism activities, daily prayer and religious events in this site have been creating various physical and social concerns. If appropriate planning measurements are not derived from the consideration of the carrying capacities of this site, tourism center will be overloaded, tourism quality will be degraded and therefore the benefit obtained from tourism activities will be reduced. For the first time in the history of this site, in this paper, we demonstrate an applicable method which is used for calculating the physical carrying capacity for this historical mosque. Also the result of SWOT model analysis regarding opportunities and limitations on number of the tourists can be used as the preliminary benchmarks for later tourism planning of the Emam mosque

Seasonal heavy precipitation sensitivity to moisture corrections in the western Mediterranean across resolutions

The controlling role of atmospheric water vapour for heavy precipitation leading to extreme events has been widely demonstrated, along with the existing gap of adequate moisture observations and the frequent biases present in model simulations concerning this fundamental variable. In this study, we profit from a state-of-the-art dense network of GPS measurements over Europe retrieving a homogenized GPS-derived Zenith Total Delay (GPS-ZTD) data set up to 10 min of temporal resolution, to assess the seasonal sensitivity of convection-related processes and heavy precipitation modelling to atmospheric humidity corrections. For this purpose, we perform nudging experiments with the COSMO-CLM model at two spatial resolutions, 7 km (parameterized convection) and 2.8 km (explicitly resolved convection) covering the autumn period of 2012, when the Special Observation Period (SOP) 1 of the Hydrological Cycle in the Mediterranean Experiment (HyMeX) program took place in the Western Mediterranean, which is our area of interest. The benefits and disadvantages of GPS-ZTD nudging and resulting moisture corrections are disentangled. The impact on high-resolution parameterized versus convection-permitting simulations is compared. A process-understanding methodology and a local-to-regional approach are used. Our results show a beneficial impact on the seasonal scale at both model grid spacings improving the representation of the chain of processes leading to heavy precipitation, contrary to the non-systematic improvement at the event and sub-event scales. The correction of atmospheric moisture entails a reduction of about 10% in the total column water vapour and corrections on single locations up to 10 mm counteracting the model wet bias across scales. The location, structure, and amount of total precipitation are positively affected. Particularly, the combination of high-resolution atmospheric humidity observations and fine convection-permitting simulations shows great potential for correction of the precipitation daily cycle, key for accurate precipitation modelling. The difference in the density of local and upstream observational networks and the lack of information on the vertical stratification of moisture are identified weaknesses, which could be determinants in obtaining more accurate corrections on seasonal to sub-seasonal scales after assimilation strategies

Association Between Vestibular Migraine and Migraine Headache: Yet to Explore.

ObjectivesTo evaluate if patients with a diagnosis of vestibular migraine (VM) by the International Classification of Headache Disorders (ICHD) criteria have meaningful differences in symptomatology and disease characteristics when compared to patients with concurrent vestibular symptoms and migraine that do not meet ICHD criteria.MethodsPatients who presented for the evaluation of vertigo were provided a detailed questionnaire about dizziness and migraine symptoms. Patients were assigned to either VM cohort (met ICHD criteria for VM) or migraine headache (MH) cohort (met ICHD criteria for migraine with or without aura but not VM). Disease characteristics, symptomatology, quality of life, and perceived stress score were compared between the cohorts.ResultsThe VM cohort demonstrated a shorter duration of vertigo episodes, 11 ± 22 hours versus 84 ± 146 hours in the MH cohort. In the VM cohort, 81% reported experiencing migraine headaches during episodes of vertigo, versus 61% in the MH cohort. All patients in the VM cohort reported a previous diagnosis of migraine headache, whereas 9% of the MH cohort had not been previously diagnosed by another physician. There was no difference in quality of life or perceived stress scores between the cohorts.ConclusionsA large proportion of vertigo patients with migrainous features do not meet the ICHD criteria for VM. The differences between cohorts represent selection bias rather than meaningful features unique to the cohorts. As such, VM and MH with vestibular symptoms may exist on a spectrum of the same disease process and may warrant the same treatment protocols

Assessing atmospheric moisture effects on heavy precipitation during HyMeX IOP16 using GPS nudging and dynamical downscaling

Gaining insight into the interaction between atmospheric moisture and convection is determinant for improving the model representation of heavy precipitation, a weather phenomenon that causes casualties and monetary losses in the western Mediterranean region every year. Given the large variability of atmospheric moisture, an accurate representation of its distribution is expected to reduce the errors related to the representation of moist convective processes. In this study, we use a diagnostic approach to assess the sensitivity of convective precipitation and underlying mechanisms during a heavy precipitation event (Hydrological cycle in the Mediterranean eXperiment Intensive Observation Period; HyMeX IOP16) to variations of the atmospheric moisture spatio-temporal distribution. Sensitivity experiments are carried out by nudging a homogenized data set of the Global Positioning System-derived zenith total delay (GPS-ZTD) with sub-hourly temporal resolution (10 min) in 7 and 2.8 km simulations with the COnsortium for Small-scale MOdeling in CLimate Mode (COSMO-CLM) model over the western Mediterranean region. The analysis shows that (a) large atmospheric moisture amounts (integrated water vapour; IWV ∼ 40 mm) precede heavy precipitation in the affected areas. This occurs 12 h prior to initiation over southern France and 4 h over Sardinia, north-eastern Italy and Corsica, which is our main study area. (b) We found that the moisture is swept from the Atlantic by a westerly large-scale front associated with an upper level low on the one hand and evaporated from the Mediterranean Sea and north Africa on the other. The latter moisture transport occurs in the 1 to 4 km layer. (c) COSMO-CLM overestimated the atmospheric humidity over the study region (Corsica), and this was, to a good extent, corrected by the GPS-ZTD nudging. This reduced maximum precipitation (−49 % for 7 km and −16 % for 2.8 km) drastically, considerably improving the precipitation representation in the 7 km simulation. The convection-permitting simulation (2.8 km) without the GPS-ZTD nudging already did a good job in representing the precipitation amount. (d) The two processes that exerted the largest control on precipitation reduction were the decrease of atmospheric instability over Corsica (convective available potential energy; CAPE −35 %) and the drying of the lower free troposphere bringing additional dry air entrainment. In addition, the 7 km simulation showed a weakening of the represented low-pressure system and the associated cyclonic wind circulation. This ultimately reduced the intensity and number of convective updrafts represented over the island. These results highlight the large impact exerted by moisture corrections on precipitating convection and the chain of processes leading to it across scales