bluuebunny/crossref_metadata_2025 huggingface dataset:
Locating regions of arrhythmogenic substrate by analyzing the duration of triggered atrial activities
Authors: Verma Bhawna , Oesterlein Tobias , Luik Armin , Schmitt Claus , Dössel Olaf
Published: September 2015

Catheter ablation is the most widely used minimum invasive technique to cure atrial arrhythmias. However, the success rate of the treatment is still moderate and depends on the experience and expertise of the physicians. The aim of this work is to present a simple and feasible method to identify the arrhythmogenic areas on the atrium based on the duration of atrial activities in the intraatrial electrograms. Depolarization waves are created by giving pacing impulses from coronary sinus (CS). The duration of the activity triggered from sinus node (SN) and pacing sequences are analysed by calculating the duration of the activity to mark regions with long atrial activity waves. The intraatrial electrograms have been analysed on the basis of temporal and spatial information. The region specific study may favour the localization of the critical sites in the patient specific atrial anatomy and aid the physician in ascertaining the efficacy of the cardiac therapies. The identification of suitable markers for critical patterns of the depolarization waves may be crucial to guide an effective ablation treatment. In this work a novel study for point-to-point analysis of the intraatrial electrograms was carried out.
Atrial and ventricular signal averaging electrocardiography in pacemaker and cardiac resynchronization therapy
Authors: Haschemi C. , Heinke M.
Published: September 2015

Cardiac resynchronization therapy with atrioventricular and interventricular delay optimized biventricular pacing is an established therapy for symptomatic heart failure patients with prolongation of QRS duration, left bundle branch block and reduced left ventricular ejection fraction. The aim of the investigation was to evaluate right atrial, right ventricular and left ventricular electrical signals of implantable electronic cardiac devices with and without signal averaging technique with novel LabVIEW software. Electrical interatrial conduction delay and inter-ventricular conduction delay may be useful parameters to evaluate electrical atrial and ventricular desynchronization in heart failure patients.
Cardiac index in atrio- and interventricular delay optimized cardiac resynchronization therapy and cardiac contractility modulation
Authors: Tumampos J. , Wulf N. , Kühnert H. , Solbrig O. , Querengässer J. , Heinke M.
Published: September 2015

Cardiac resynchronization therapy (CRT) is an established therapy for heart failure patients and improves quality of life in patients with sinus rhythm, reduced left ventricular ejection fraction (LVEF), left bundle branch block and wide QRS duration. Since approximately sixty percent of heart failure patients have a normal QRS duration they do not benefit or respond to the CRT. Cardiac contractility modulation (CCM) releases nonexcitatoy impulses during the absolute refractory period in order to enhance the strength of the left ventricular contraction. The aim of the investigation was to evaluate differences in cardiac index between optimized and nonoptimized CRT and CCM devices versus standard values. Impedance cardiography, a noninvasive method was used to measure cardiac index (CI), a useful parameter which describes the blood volume during one minutes heart pumps related to the body surface. CRT patients indicate an increase of 39.74 percent and CCM patients an improvement of 21.89 percent more cardiac index with an optimized device.
The role of expert evaluation for microsleep detection
Authors: Golz M. , Schenka A. , Sommer D. , Geißler B. , Muttray A.
Published: September 2015

Recently, it has been shown by overnight driving simulation studies that microsleep density is the only known sleepiness indicator which rapidly increases within a few seconds immediately before sleepiness related crashes. This indicator is based solely on EEG and EOG and subsequent adaptive pattern recognition. Accurate microsleep recognition is very important for the performance of this sleepiness indicator. The question is whether expensive evaluations of microsleep events by a) experts are necessary or b) non-experts provide sufficient evaluations. Based on 11,114 microsleep events in case a) and 12,787 in case b) recognition accuracies were investigated utilizing (i) artificial neural networks and (ii) support-vector machines. Cross validated classification accuracies ranged between 92.2 % for (i,b) and 99.3 % for (ii, a). It is concluded that expert evaluations are very important to provide independent information for detecting microsleep.
New NIR spectroscopy based method to determine ischemia in vivo in liver – a first study on rats
Authors: Lange Matthias , Liebold Stephanie , Kan Chunyi , Dahmen Uta
Published: September 2015

In this study we analysed ischemic rat liver lobes with Near Infrared Spectroscopy (NIRS) to evaluate the potential of NIRS as predictor of ischemic reperfusion injury (IRI). We were able to predict duration of ischemia using visible and near infrared light.
Evaluation of CT capability for the detection of thin bone structures
Authors: Gudfinnsdottir H. , Helgason T.
Published: September 2015

Evaluation of CT capability for the detection of thin bone structures by means of modeling small bone structures and comparing with quantitative measurements. Knowledge of how thin bone structures can be or of what low density to be detectable in clinical CT images can increase the diagnostic competence to diagnose various diseases. Correlation between size and density of detectable bone structures is the key for many diagnosis purposes. This paper describes the use of clinical 64 detector scanner to image the skeletons of codfish and salmon species. Fish skeletons, such as codfish and salmon, have petite structures and lower bone density than humans. Bone structures were segmented out of the image data and 3D models of their skeletons developed. Evaluation was done by means of comparing quantitative measurements of selected bones to parameters observed from the model. Results show the limits where thin bones and of low density disappear from the clinical CT. It shows ability to reconstruct closely the diameter of the codfish bones but to a less extent the small bones of the salmon.
Tissue segmentation from head MRI: a ground truth validation for feature-enhanced tracking
Authors: Wissel Tobias , Stüber Patrick , Wagner Benjamin , Schweikard Achim , Ernst Floris
Published: September 2015

Accuracy is essential for optical head-tracking in cranial radiotherapy. Recently, the exploitation of local patterns of tissue information was proposed to achieve a more robust registration. Here, we validate a ground truth for this information obtained from high resolution MRI scans. In five subjects we compared the segmentation accuracy of a semi-automatic algorithm with five human experts. While the algorithm segments the skin and bone surface with an average accuracy of less than 0.1 mm and 0.2 mm, respectively, the mean error on the tissue thickness was 0.17 mm. We conclude that this accuracy is a reasonable basis for extracting reliable cutaneous structures to support surface registration.
Analysis of the release kinetics of surface-bound proteins via laser-induced fluorescence
Authors: Pollack Thomas , Dangers Marc , Seitz Hermann
Published: September 2015

The drying and resolving processes of surface-bound proteins were analysed with a stereoscopic microscope combined with laser-induced fluorescence (LIF) with the aim to assist the advancement of a semiautomated point-of-care allergy diagnostic device. The results shown in this paper present the use of the LIF-method for concentration calibration and the analysis of drying and resolving dyed proteins. The method is established successfully and delivers precise results.
Wireless medical sensors – context, robustness and safety
Authors: Bollmeyer Christian , Pelka Mathias , Gehring Hartmut , Hellbrück Horst
Published: September 2015

Wireless medical sensors are an emerging technology. Wireless sensors form networks and are placed in an unknown environment. For indoor scenarios context detection of medical sensors, e.g. removal of sensors from a specific room, is important. Current algorithms for context detection of wireless sensors are based on RF signals, but RF signal propagation and room location show only a weak correlation. Recent approaches with RSSI-measurements are based on prior fingerprinting and therefore costly. In our approach, we equip wireless sensor nodes with a barometric sensor to measure pressure disturbances that occur, when doors of rooms are opened or closed. By signal processing of these disturbances our proposed algorithm detects rooms and estimates distances without prior knowledge in an unknown environment. Based on these measurement we automatically build a topology graph representing the room context and distances for indoor environment in a model for buildings. We evaluate our algorithm within a wireless sensor network and show the performance of our solution.
A muscle model for hybrid muscle activation
Authors: Klauer Christian , Irmer Maximilian , Schauer Thomas
Published: September 2015

To develop model-based control strategies for Functional Electrical Stimulation (FES) in order to support weak voluntary muscle contractions, a hybrid model for describing joint motions induced by concurrent voluntary-and FES induced muscle activation is proposed. It is based on a Hammerstein model – as commonly used in feedback controlled FES – and exemplarily applied to describe the shoulder abduction joint angle. Main component of a Hammerstein muscle model is usually a static input nonlinearity depending on the stimulation intensity. To additionally incorporate voluntary contributions, we extended the static non-linearity by a second input describing the intensity of the voluntary contribution that is estimated by electromyography (EMG) measurements – even during active FES. An Artificial Neural Network (ANN) is used to describe the static input non-linearity. The output of the ANN drives a second-order linear dynamical system that describes the combined muscle activation and joint angle dynamics. The tunable parameters are adapted to the individual subject by a system identification approach using previously recorded I/O-data. The model has been validated in two healthy subjects yielding RMS values for the joint angle error of 3.56° and 3.44°, respectively.
A java based simulator with user interface to simulate ventilated patients
Authors: Stehle P. , Lehmann T. , Redmond D. , Möller K. , Kretschmer J.
Published: September 2015

Mechanical ventilation is a life-saving intervention, which despite its use on a routine basis, poses the risk of inflicting further damage to the lung tissue if ventilator settings are chosen inappropriately. Medical decision support systems may help to prevent such injuries while providing the optimal settings to reach a defined clinical goal. In order to develop and verify decision support algorithms, a test bench simulating a patient’s behaviour is needed. We propose a Java based system that allows simulation of respiratory mechanics, gas exchange and cardiovascular dynamics of a mechanically ventilated patient. The implemented models are allowed to interact and are interchangeable enabling the simulation of various clinical scenarios. Model simulations are running in real-time and show physiologically plausible results.
Test setup for characterizing the efficacy of embolic protection devices
Authors: Matthies J.-B. , Kurzhals A. , Schmidt W. , Atamna A. , Andresen R. , Schmitz K.-P. , Grabow N.
Published: September 2015

Systems for embolic protection are applied during the dilatation and the implantation of stents in the carotid artery. They are used to avoid downstream drift of arterial plaque particles which may be released during the intervention. Such particulate debris increases the risk of stroke when reaching and occluding even minor cranial vessels. Embolic protection devices (EPD) are intended to collect such particles during intervention and to finally remove them.

A test setup was developed in order to assess the effi-cacy of commercially available EPDs. The setup considers the introduction of relevant particles, as well as typical anatomic conditions. The EPDs could be tested using curved and ovalized vessel types to simulate stressed vessel conditions. Furthermore, a method for counting the particles was established to quantify collected particles in the EPD, the leaked particles and those which were left behind in the vessel.
Electrospun vascular grafts with anti-kinking properties
Authors: Bode M. , Mueller M. , Zernetsch H. , Glasmacher B.
Published: September 2015

One of the major challenges in developing appropriate vascular substitutes is to produce a graft that adapts to the biological and mechanical conditions at the application or implantation site. One approach is the use of tissue engineered electrospun grafts pre-seeded with autologous cells. However, bending stresses during in vivo applications could lead to kinking of the graft which may result in life-threatening stenosis. The aim of this study was to develop an electrospun vascular graft consisting of biodegradable polymers which can reduce or prevent kinking, due to their higher flexibility. In order to improve the bendability of the grafts, various electrospinning collectors were designed using six different patterns. Subsequently, the grafts were examined for scaffold morphology, mechanical strength and bendability. Scaffolds spun on a collector structured with a v-shaped thread (flank angle of 120°) showed a homogenous and reproducible fiber deposition as compared to the unstructured reference sample. The results of the tensile tests were comparable to the unstructured reference sample, supporting the first observation. Studies on bendability were performed using a custom made flow-bending test setup. It was shown that the flow through the v-shaped grafts was reduced to less than 45 % of the reference value even after bending the graft to an angle of 140°. In contrast, the flow through an unstructured graft was reduced to more than 50 % after bending to an angle of 55°. The presented data demonstrate the need for optimizing the bendability of the commonly used electrospun vascular grafts. Using of macroscopic v-shaped collectors is a promising solution to overcome the issue of graft kinking.
Knowledge and attitude about pubertal health and their socio-demographic predictors in Iranian adolescents
Authors: Saghi Sima , Mirghafourvand Mojgan , Alizadeh Charandabi Sakineh Mohammad , Nabighadim Abbas , Seidi Simin , Rahmani Azad
Published: September 2015

Background:

Adolescence is a critical period and is associated with physical and psycho-social changes induced by puberty, which builds personality, behavior, and future health of the adolescents. This study aimed to determine the adolescent’s knowledge and attitude toward pubertal health and his/her socio-demographic predictors.

Methods:

This cross-sectional study was performed on 1017 adolescent girls who were in the second and third grades of secondary schools in Tabriz, Iran, in 2013. The sampling method was random. The general linear model was used to determine the social-demographic predictors of the adolescent’s knowledge and attitude about pubertal health.

Results:

The mean (standard deviation) score of knowledge and attitude was 53.2 (13.7) and 66.7 (11.5), respectively (from an attainable score range of 0–100). The variables of educational level, economic status, household members, obtaining information about the puberty, and age of menarche were predictors of knowledge. Educational level, the most feeling at menarche, and source of the most information about puberty were predictors of attitude (p<0.05).

Conclusion:

The findings of this study show that the knowledge and attitude of adolescents about pubertal health are moderate. Thus, it is necessary to educate the girls about pubertal health to enable them to have a healthy reproductive life in the future.
Character strengths and service leadership
Authors: Shek Daniel T.L. , Yu Lu
Published: September 2015

Character strengths refer to the moral aspects of personality that have multiple dimensions. As a basic requirement of a service leader, character strengths provide the most inherent power for fulfilling different tasks and pursuing continuous development. In this paper, a lecture that aims to foster character strengths in undergraduate students is introduced. The theoretical foundation of the lecture on character strengths is first presented, including the concepts and theories related to character strengths, their relevance to service leadership and methods to promote the development of character strengths. The basic content and activities designed for this particular lecture are then outlined for the reader to have an overall view of the lecture. Finally, reflection on the role of the lecturer in the cultivation of character strengths in students and additional topics for consideration are highlighted.
Eulerian-Eulerian Simulations of Segregating Binary Gas-Solid Fluidized Beds
Authors: Coroneo Mirella , Mazzei Luca , Lettieri Paola , Montante Giuseppina , Paglianti Alessandro
Published: September 2015

This work is aimed at investigating a bidisperse gas-solid fluidized bed by Computational Fluid Dynamics simulations. The selected simulation approach is based on the Eulerian unsteady equations of motion for each phase coupled with a model based on the granular kinetic theory. The effect of grid size and time step on axial segregation of two different binary solid mixtures is investigated. The analysis of the simulation results, which strengthen previous findings with new data, confirms that firm conclusions on the capacity of the CFD model to predict the segregation dynamics in fluidized beds can be drawn only after careful verification of numerical uncertainties at the operating conditions under investigation. The relationship between the average absolute error, which is evaluated by comparison of the simulation results with literature experimental data, and a global parameter, which takes into account both the operating conditions and the spatial and temporal resolutions, is shown.
Numerical Studies on the Performance of Scramjet Combustor with Alternating Wedge-Shaped Strut Injector
Authors: Choubey Gautam , Pandey K. M.
Published: September 2015

Numerical analysis of the supersonic combustion and flow structure through a scramjet engine at Mach 7 with alternating wedge fuel injection and with three angle of attack (
KHASIAT JAMU CEKOK TERHADAP PENINGKATAN BERAT BADAN PADA ANAK
Authors: Marni Marni , Ambarwati Retno
Published: September 2015

Anak usia di bawah lima tahun sering mengalami penurunan nafsu makan, yang mengakibatkan berkurangnya asupan nutrisi sehingga berat badan menurun. Penelitian ini bertujuan untuk mengetahui khasiat  ramuan jamu cekok terhadap peningkatan berat badan pada anak. Metode penelitian : penelitian kualitatif,  pengumpulan data dilakukan pada keluarga yang memberikan jamu cekok pada anak balitanya, dukun bayi/pembuat jamu, herbalis dan petugas kesehatan. Penelitian dilakukan pada bulan Maret-Juni  2014, di wilayah Puskesmas Selogiri dengan pendekatan kualitatif, Seluruh rangkaian dan cara kerja ataupun proses penelitian kualitatif ini berlangsung secara serentak dilakukan dengan  pengumpulan, pengolahan, menginterpretasikan sejumlah data dan fakta yang ada  selanjutnya disimpulkan dengan metode induktif. Hasil penelitian : ramuan jamu cekok berkhasiat meningkatkan berat badan adalah: temu ireng ( curcuma aeroginosa), temulawak (curcuma xanthorriza robx), kencur (kaempferla galanga L), Meniran (Phyllanthus niruri), lempuyang emprit (zingiber americans), daun pepaya (carica papaya l), kunyit (curcuma domestica val), sambiloto dan tempe busuk.

 

Toodler get a decreasing of their appetite, that causes the reducing of nutrition so their weght reduce. This research purposes to know the function of cekok herbal and the benefits to weight gain in children. Research Method: qualitative research, Colleting data is got from the family that give the herbal medicine of cekok in toddler, herbal medicine maker, herbalist and paramedics. The study was conducted in March and June 2014 in the PHC Selogiri area by using qualitative approach. All of sequance or processing of qualitative research took place simultaneously. The result: The ingredients Cekok has function to promote the weight, there are : Curcuma aeroginosa, Curcuma xanthorriza robx, kaempferla galanga L, Meniran Phyllanthus niruri, Zingiber americans, Carica papaya l, (curcuma domestica val), bitter and rotten tempeh.
Túl az impaktfaktoron. Gondolatok Stefanie Haustein könyve nyomán
Authors: Schubert András
Published: September 2015

The excellent book on multidimensional journal evaluation by Stefanie Haustein helps to find the place of the impact factor in the complex system of journal evaluation indicators. By delimiting the dimensions of evaluation and the user groups, the author of the book creates a framework that serves as a novel and useful guidance both for the lay reader and the expert. Orv. Hetil., 2015, 156(38), 1551–1552.
O que finda é o que fica: tradição em jogo, ensaio em xeque
Authors: Felippe Eduardo Ferraz
Published: September 2015

Este ensaio ilumina a atenciosa meditação de Lezama Lima acerca da tradição latino-americana. A princípio, diferencia-se da tradução cultural de Alejo Carpentier. Em seguida, em sua análise de T.S. Eliot e de Ernst Robert Curtius, relaciona tradição e historicidade, ao mesmo tempo em que coloca em seu centro o problema da experiência histórica, por meio da figura retórica da emulação. Por fim, esse conjunto de argumentos examina a visão histórica pela poesia como sua questão central. Inspira, assim, outros recursos para a historiografia por meio de sua crítica ao historicismo e a ênfase no reconhecimento.
Evaluation of Aminocyclopyrachlor Herbicide for Turf Tolerance and Weed Control on Florida Roadside Right-of-Ways
Authors: Durham Michael W. , Ferrell Jason A. , Minogue Patrick J. , MacDonald Gregory E. , Sellers Brent A.
Published: September 2015

Aminocyclopyrachlor (AMCP) is a pyrimidine carboxylic acid herbicide that is being evaluated for weed control on highway right-of-ways. The goal of this study was to evaluate weed control capabilities and tolerance of desirable turf to AMCP. The objective of the weed efficacy trial was to determine if AMCP (66, 132, and 263 g ai ha−1) was as effective as aminopyralid (18, 53, and 88 g ai ha−1) for controlling two weed species, mat lippia andBidens alba. In 2011, AMCP applied at 132 g ai ha−1resulted in 93% control of mat lippia at 2 mo after treatment (MAT) and 65% control at 3 MAT. In 2012, AMCP at 66 or 132 g ha−1resulted in 93 to 97% control of mat lippia, respectively, at 3 MAT. Aminopyralid, applied POST, never exceed 10% control of mat lippia in 2011 and 60% control in 2012. AMCP, applied POST, at 66 g ha−1, controlled ofB. alba84%, similar to the 89% control seen with aminopyralid at 88 g ha−1. The level of control from AMCP of the two weed species was equal to or greater than aminopyralid. An additional objective was to determine the tolerance of common bermudagrass and ‘Pensacola' bahiagrass to AMCP (66, 132, and 263 g ai ha−1) and imazapic (35 and 70 g ai ha−1) applied alone and in combination. Applications were made in late spring during seedhead initiation. No additional chlorosis was detected when imazapic was applied in combination with AMCP for either turf species. Averaged across imazapic rates, AMCP at 66 and 132 g ha−1, within the suggested rate range (48.5–132 g ai ha−1), did not cause greater than 25% chlorosis at any time. Chlorosis observed for AMCP applied alone and in combination with imazapic was acceptable and decreased to zero by 8 to 10 wk after treatment.
E-government Implementation in Mozambique: Transferring Lessons across the Public Secto
Authors: Macueve Gertrudes
Published: September 2015

Although the implementation of computerized information systems in developing countries has been ongoing for decades, the

diffusion process has been slow to achieve a state of active use in organizational settings, and examples of cross-sector sharing

and learning remain very limited. This paper aims at demonstrating aspects that can be shared across sectors within the same

socio-economic and political implementation context, and the potential benefits that can be achieved. Empirically, the paper

draws upon experiences from the study of information systems implementation within the health and land management sectors

respectively in Mozambique. The concept of “translation” drawn from Actor-Network-Theory (ANT) is used as a lens to analyse

both experiences, and the similarities and differences are analyzed to draw specific inferences on potential domains of crosslearning.

Specific learning concerns the issues around managing the scalability and sustainability of the implementation of egovernment

initiatives. Four key areas of learning identified through this analysis are: use of participatory and action research

development; enrolment of the government; enrolment of local universities; and use of joined top-down and bottom-up

implementation approach.
Using e-coins to ensure fair sharing of donor funds amongst HIV healthcare facilities
Authors: Olivier Martin S , Eloff JHP , Venter Hein S , Botes Mariëtte E
Published: September 2015

Donor funds are available for treatment of many diseases such as HIV. However, privacy constraints make it hard for donor organisations to verify that they have not sponsored the same patient twice --- or sponsored a patient whose treatment was also sponsored by another donor.

This paper presents a protocol based on digital cash that enables donor organisations to obtain a proof (in the form of an e-coin) from healthcare providers for patients such a provider claims to have treated. These coins are distributed to patients at the beginning of a funding cycle.

The major challenge is to issue a unique coin to a patient --- even if the coin is reissued. This is achieved without giving anyone access to a national database of identities; all databases contain effectively concealed information. Reissued coins will be identical to previous coins with a probability that can be decided beforehand.
A Study of Evolutionary Algorithm Selection Hyper-Heuristics for the One-Dimensional Bin-Packing Problem
Authors: Pillay Nelishia
Published: September 2015

Hyper-heuristics are aimed at providing a generalized solution to optimization problems rather than producing the best result for one or more problem instances. This paper examines the use of evolutionary algorithm (EA) selection hyper-heuristics to solve the offline one-dimensional bin-packing problem. Two EA hyper-heuristics are evaluated. The first (EA-HH1) searches a heuristic space of combinations of low-level construction heuristics for bin selection. The second (EA-HH2) explores a space of combinations of both item selection and bin selection heuristic combinations. These EA hyper-heuristics use tournament selection to choose parents, and mutation and crossover with hill-climbing to create the offspring of each generation. The performance of the hyper-heuristics is compared to that of each of the low-level heuristics applied independently to solve this problem. Furthermore, the performance of both hyper-heuristics is also compared. The comparisons revealed that hyper-heuristics in general perform better than any single low-level construction heuristic in solving the problem. In addition to this it was found that the hyper-heuristic exploring a space of both item selection and bin selection heuristic combinations is more effective than the hyper-heuristic searching a space of just bin selection heuristic combinations. The performance of this hyper-heuristic was found to be comparable to other methods applied to the same benchmark sets of problems.
To Mature or not to Mature: The Information Systems Conundrum
Authors: Marnewick Carl
Published: September 2015

Research has been done within the South African information technology (IT) industry over the last decade with regard to project management maturity (PMM) and the impact it has on delivering information systems (IS) projects successfully. The research was done to determine whether IS PMM per knowledge area has improved over the last decade. It investigates if there is a correlation between maturity levels and project success. Four independent surveys over the last decade focused on IS PMM and the longitudinal analysis provides a benchmark for whether IS PMM has increased or not. This article focuses on whether certain knowledge areas are more of a problem within the IT industry and to determine what the overall IS PMM is. The longitudinal analysis indicates trends and highlights areas of concern. It indicates that most IT companies are still operating at level 3 and that risk and procurement management are the knowledge areas of concern. A comparative analysis indicates that there is no difference between South African and international maturity levels. The results provide a South African perspective of IS PMM. It highlights that risk management is still a knowledge area that is neglected and that emphasis must be placed on managing risk within IT projects.
A conceptual framework for cyber security awareness and education in SA
Authors: Kortjan Noluxolo , Von Solms Rossouw
Published: September 2015

The Internet is becoming increasingly interwoven in the daily lives of many individuals, organisations and nations. It has, to a large extent, had a positive effect on the way people communicate. It has also introduced new avenues for business; and it has offered nations an opportunity to govern online. Nevertheless, although cyberspace offers an endless list of services and opportunities, it is also accompanied by many risks, of which many Internet users are not aware. As such, various countries have developed and implemented cyber-security awareness and education measures to counter the perceived ignorance of the Internet users. However, there is currently a definite lack in South Africa (SA) in this regard; as there are currently, little government-led and sponsored cyber-security awareness and education initiatives. The primary research objective of this paper, therefore, is to propose a cyber-security awareness and education framework for SA that would assist in creating a cyber-secure culture in SA among all of the users of the Internet. This framework will be developed on the basis of key factors extrapolated from a comparative analysis of relevant developed countries.
The effects of grazing on foliar trait diversity and niche differentiation in Tibetan alpine meadows
Authors: Niu Kechang , Messier Julie , He Jin-Sheng , Lechowicz Martin J.
Published: September 2015

Niche differentiation arising in functional trait diversity is expected to increase the potential for species coexistence, but empirical evidence for these relationships is sparse. We test whether grazing increases the functional diversity of leaf traits and niche differentiation in phosphorus limited Tibetan alpine meadows. We measured five traits in the leaf economic spectrum (LES; LC, leaf carbon concentration; LN, leaf nitrogen concentration; LP, leaf phosphorus concentration; SLA, specific leaf area; and LDMC, leaf dry matter content) for all species occurring in grazed and ungrazed plots at each of five sites. By comparing indicators of the fundamental and realized niches of co‐occurring plants in both grazed and ungrazed plots, we quantified a grazing‐mediated competitive effect on trait divergence and convergence. This trait response reflects the relative importance of niche differentiation and competitive exclusion in response to grazing. We found that while grazing induced LP divergence, both LC and LN tended to converge under grazing. Grazing had no effect on either SLA or LDMC diversity. When all five traits are considered together as a functionally integrated suite (LES hypervolume), there is no evidence for either divergence or convergence in response to grazing. Although grazing promotes functionally relevant diversity in LP that enables niche differentiation in competition for scarce soil available P, these results suggest that coordinated shifts in other LES traits sustain effective overall foliar function despite shifts in LP.
Organically Crosslinked Polymer Sealant for Near-Wellbore Applications and Casing Integrity Issues: Successful Wellbore Interventions
Authors: Vasquez Julio , Santin Yoann
Published: September 2015

Wellbore integrity issues, including casing leaks and poor zonal isolation behind the casing, present a tremendous challenge to conventional cement slurries when dealing with low injectivity, pressure restrictions, pin-hole leaks, and/or a primary cementing microannulus, among others. If the conditions of these near-wellbore (NWB) issues exceed the capabilities of conventional cement slurries, alternative methods might be necessary. This paper presents the field implementation of an organically crosslinked conformance polymer sealant (CPS) system used successfully to address these wellbore integrity challenges. Although it is not a replacement for cement slurries in all situations, the CPS system provides an alternative chemical and engineering solution for treating NWB problems in special circumstances.

The CPS system uses a copolymer of acrylamide and t-butyl acrylate (PAtBA) crosslinked with polyethyleneimine (PEI). The CPS system is injected into the formation and void spaces as a low viscosity solution that activates at a predicted time to form a hydrogel to completely shut off matrix permeability, fractures, fissures, and/or channels. This system has been successfully tested to withstand a differential pressure of at least 2,600 psi, has a working temperature range of 40 to 400°F, and is resistant to acid, CO2, and H2S environments. The CPS system does not develop any compressive strength, which simplifies the cleanup stage by easily jetting it out of the wellbore, opposed to cement that has to be milled out, which becomes increasingly challenging at shallow depths and/or in highly deviated wells.

To date, more than 1,000 CPS system treatments have been performed globally to address conformance problems, such as water coning/cresting, high-permeability streaks, gravel-pack isolation, and/or fracture shutoff. In this paper, case histories related to casing-leak repair, annular flow between pipes, and poor zonal isolation behind the casing are presented. Additionally, lessons learned from the diagnostic stages of both offshore and inland case histories are highlighted.
An Innovative Approach to Formation Evaluation with a Sourceless LWD Technology for the First Time in Joint Operations, A Case Study From Partitioned Zone Between Kuwait and Saudi Arabia
Authors: Al-Rubaiyea Jamal , Al-Bader Ahmad , Al-Houli Meshari , Al-Najim Abdul-aziz , Al-Duwaish Majed , Elsherif Ahmed
Published: September 2015

The South Fuwaris Field is located in the Partitioned Zone between Kuwait and Saudi Arabia. The Lower Cretaceous Ratawi reservoirs were discovered in 1961, and production commenced in 1963. There are two major reservoirs – the Ratawi Limestone, which is predominantly developed by vertical wells, and the Ratawi Oolite, which is exclusively developed by horizontal wells. The reservoirs comprise low-moderate permeability limestones.

The use of Logging While Drilling (LWD) tools which utilise natural radioactive sources has been always risky since losing radioactive source will necessitates a complex procedure to abandon side track the hole.

Recently, a new LWD logging technique that incorporates Pulsed Neutron Generators (PNG) was introduced to Wafra Joint Operations (WJO). This new technique acts generates multiple measurements (Resistivity / Density / Neutron / Sigma / Spectroscopy). The PNG uses electrical power generated from the measurement-while-drilling (MWD) turbine to generate a large cloud of fast neutrons. These fast neutrons interact with the formation atoms to generate formation hydrogen index, sigma, and spectroscopy data. In addition, the fast neutron interactions generate a secondary gamma ray cloud that can be used to measure formation density (similar to standard density measurement).

This innovative technique was used for the first time for Wafra Joint Operations in the South Fuwaris Field, with great success. The tool was run in a pilot hole with an inclination of 60°, cutting the Ratawi Limestone and Ratawi Oolite reservoirs. The acquired data were of excellent quality in comparison with conventional LWD data.

The formation sigma was used in the water saturation calculations. Spectroscopy analysis was also recorded and used for formation evaluation, especially for clay content.

Finally, the new technique has been proven as a good risk mitigation / elimination for future operations.
Produced Water Monitoring and Developing Risk Profiles for Produced Water Re-Injection
Authors: Bhola N , Ariaratanam G , Roth N
Published: September 2015

Online particle measurement is one of the key technologies in characterising fluid quality and developing strategies to ensure the efficient operation of and optimise any separation process. Online imaging systems have the benefit of being able use their multi-dimensional data to provide more information than just particle size, as particle shape, aspect ratio and many other parameters measured can be used to identify and classify different types of particulates, such as oil droplets and solid particles in a produced water system.

This understanding of particle type, size and shape provides a significant step forward over simple particle size as it enables separation process design and operation to specifically treat and remove target particulates. In this paper we will examine case studies that demonstrate how specific particle information can be used to understand and optimise different treatment stages within a produced water treatment system.

Agglomerates appear frequently in some fluid systems and can confuse imaging systems where simple parameters are being used to differentiate between particle species as the agglomerated material will present with different shape characteristics to those of its individual constituent particles. We will review produced water systems where the chemicals used to aid separation, and some of the separation technologies themselves, operate by creating aggregation and agglomeration using case studies demonstrating these effects.

We will discuss where agglomerates commonly occur and what significance these particles have within the oily water separation process. We will review the latest imaging software package that is capable of identifying these types of agglomerated particles and assessing constituent components.

Finally we will assess how this information contributes to our understanding of the risk profile that these types of agglomerated materials present in produced water re-injection and how that risk profile may be developed and analysed in the future.
An Integrated Petrophysical, Geochemical and Operational Approach to Identify Unconventional Resource, Case Study, Obaiyed Field, Western Desert-Egypt.
Authors: Ghanima Ahmed , El Bendary Ahmed , Taha Ahmed , Farag Yasser , Gamal Ahmed , Abbas Sabry Aboel , Samantray Ajay , Ibrahim Haitham
Published: September 2015

Histrorically, Upper Safa is considered to be the source rock of the gas and condensate accumulated in Lower Safa stratum in Obaiyed Field. Both of Upper and Lower Safa units are parts of Khatatba formation “Jurassic age, Western Desert coulumn, Egypt”. The integration of all petrophysical and geochemical data indicated that, there is a rich organic Carbon embedded in the formation with a high britteleness ratio. As a result of the opportunity identification, there is an operational scope being studied now to proceed with a haydrulic fracturing stimulation targeting the sweet intervals “Intervals of high TOC and high Britteleness ratio” aiming to maximize the whole gas and condensate production of the field. This paper is summarizing the opportunity identification process and results using available petrophysical and geochemical data.

Six wells had been used in this study where there is a complete set of well and continuous petrophysical data exist in all of them supported by geochemical analysis reports. Specific interpretation techniques were utilized to identify the opportunity from the logs. The property of Total Organic Carbon was estimated from logs using standered DeltaLogR Passey Technique and then verified using measured data. The rock briteleness property was estimated from avilable acoustic sonic logs “Compressional and Shear slowness”. The type of Kerogen and level of Maturity were recognized from geochemical sources. The data integration provided a well identification of the shale gas opportunity.

As a part of complete assessment study of unconventional resources, a dedicated subsurface team was formed in order to evaluate the connectivity of Upper Safa, estimate the in place volumes and define the development options. The team also proposed on short term scale performing a vertical hydraulic fracturing in one of the sweet wells in order to prove the evaluation concept and increase total field production.

The success of this project is measured by three aspects: first, proving the presence of commercial shale gas plays in Upper Safa unit, second, maximizing the gas and condensate production from the field and finally, on the long term scale, unlocking commercial unconventional gas resource for future generations in Western Desert, Egypt.
A Case Study of Real-Time Drilling Optimization to Improve Well Delivery through Enhancing Drilling Rates and Identifying Invisible Lost Time to Improve Performance
Authors: Zakariya Rafik , Zein Alaa , Diab Emad , Lotfy Amr , Marland Chris , Obaidli Yaqoub Yousif , Braik Haitham Ali , Amin Mohamed Sameer , Attalah Mohamed
Published: September 2015

As the oil and gas industry expands into evermore challenging environments with more complicated processes and designs, minimizing well cost and ensuring the best use of resources has resulted in an increase in the engineering planning and field-execution requirements. Drilling optimization has changed from simply improving the rate of penetration (ROP) to analyzing all aspects of the drilling process by establishing an integrated workflow that enables different engineering departments to plan and execute the well.

In this case history, the operator’s challenges included vibration in horizontal sections, hydraulics, and wellbore integrity concerns resulting from narrow mud weights available to minimize reservoir damage and to control pore pressure.

Drilling optimization also includes measuring and improving operational efficiency and consistency. Many activities are required in a drilling operation, and the inefficiency of these activities increases well costs. This inefficiency can be described as invisible lost time (ILT), which has been shown to contribute to up to 15% of total well cost. It exposes open holes to longer elapsed times which causes hole problems, especially in reactive formations.

This case study takes a holistic look at the drilling performance and efficiency improvements that can be made by planning, modeling, and introducing a collaborative drilling engineering team with a real-time field execution team to analyze drilling challenges and address those challenges for future developments.
Generic Approach of Integrating Core Data, and Petrophysical Interpretation to Generate Reliable Facies Model in Absence of Seismic Attribute Analysis- West Qarun Field Case Study
Authors: Mira Ali , El-Behairy Amr , El-Rahman Mohamed M.Abd , Naby Mohamed Abdel , Rizk Mahmoud
Published: September 2015

No doubt that facies modelling process is a key process during building the static model which dominates all the petrophysical distribution after that. One of the best way to describe the facies change laterally across the reservoir is seismic attributes interpretation. However; unfortunately seismic attribute doesn't show accurate results in Western Desert in Egypt mostly because the reservoirs thickness is relative small.

Several trials on seismic attributes were performed during performing a study on West Qarun field which is located in Abu El-Gharadig basin, Western Desert, Egypt but without reaching conclusive results. West Qarun wells are producing mainly from Middle Abu Rawash “G”, and Lower Abu Rawash “G” reservoirs which their thickness ranges from 30 to 60 ft.

This paper presents another approach that was utilized to create facies log for each well integrating the petrophysical interpretation output and the core data as well. After that a thickness map for each facies per each reservoir was created. The resulted maps were utilized for facies model creation and consequently dominated the petrophysical properties distribution: porosity, permeability, and initial water saturation.

Permeability-Porosity relationship was described as a function of flow zone indicator (FZI) considering the distributed facies model. Defining FZI range for each facies type yields to more accurate reservoir characterization and prevents usage of unreliable permeability multipliers during history match process.

In spite of the absence of seismic attributes conclusive results, the resultant model showed excellent results during dynamic model in terms of production potential of different areas of the reservoir and the connectivity between different wells. The model showed good well by well match, total field match specially the ongoing pilot water injection project and also helped in planning the complete water injection project.
A Process-Oriented Approach for Assisted-History Matching and Calibrating Comingled production Wells Using Post-Production RFT Data and The Recently Commercialized Optimization Techniques- Ganna Field Case Study
Authors: Mira Ali , El-Behairy Amr , El-Rahman Mohamed M.Abd , El-Ghattas Ahmed
Published: September 2015

Ganna field is a part of North Bahariya concession which is located in Abu El-Gharadig basin, Western Desert, Egypt. The field was discovered and started production in 2004 through the well Ganna-1 from Middle Abu Roash “G” reservoir. Five main reservoirs were tested and produced during the field life namely Abu Roash “E”, Upper Abu Roash “G”, Middle Abu Roash “G”, Lower Abu Roash “G”, and Upper Bahariya. A 3D reservoir simulation study was performed to aid in field future development.

Major challenges appeared during history matching process. The main challenge was the commingled production wells producing from multiple reservoirs with different characteristics. Even most of the static pressure points were measured commingle as well.

Post-production RFT data was the key utilized to calibrate the history match and reach the most accurate reservoir characterization for each reservoir individually. The history match strategy depended only on global modifications using the new commercialized optimization techniques.

Previously, model calibration or history matching has commonly been conducted on a single deterministic model by “manual” or “Trial and Error” approach. With recent advances in the application of uncertainty and optimization in numerical reservoir simulation it became a must to assess the effect of different parameters not only during history matching but also its effect on the forecast through producing a probabilistic forecasting (3). The feasibility of using the manual history matching with a single deterministic model has become questionable.

A Physically-sound proper set of parameters with realistic ranges are introduced at each stage of the process in logical order and introduced to optimizers to get the best history matched case with a possibility of considering more than one history matched case for a probabilistic forecasting scenarios (4).

This paper will present the approach utilized for calibrating the comingled production wells throughout post-production RFT data using the new uncertainty & optimization module to obtain the best global matched model.