Abstract

     Nonlinear dynamic of a flexible slender truss-structure mounted manipulator for on-orbit assembly, which can be simplified as a beam–rotating link interaction system, is theoretically investigated. The governing partial differential equations (PDEs) of beam with time-varying coefficients is established by using the D’Alembert principle incorporated with the moment balance method where the beam is of a Euler–Bernoulli type and the influence of slope is considered. Such system is a typical parametrically excited system. The multiple scales method is used to determine the approximate solution and the conditions of the primary resonance ( ω1≈ωref ) and sub-harmonic resonance ( ω1≈ 2ωref , ω1≈ 3ωref and ω1≈ 4ωref ) are obtained. In addition, the nonlinear response, stability and bifurcations for primary and sub-harmonic resonance conditions have also been investigated by varying system parameters. Moreover, the results of some specific conditions by the perturbation analysis are compared with the numerical solution and are found to be in good agreement. This work has certain guiding significance for autonomous on-orbit assembly task and the method can be extended to the more general three-dimensional case.

Introduction

     Future space exploration puts forward some new requirements of space structure, such as establishment of large space solar power plants to cope with energy depletion which is huge volume (from thousands of meters or even dozens of kilometers). To meet the requirements of such space missions, the space structures will be constructed too large to be launched and deployed as a whole [1]–[5]. It is identified as one of the most appealing solutions in which the manipulator is mounted on the long truss-structures to assemble or maintain the several adjacent blocks [6]. One problem of great concern is that of low-frequency structure may be easily excited by high-frequency robotic and hardly damped out in space environment due to the low-damping characteristics of the flexible structures [2], [7]. The vibration may cause inaccuracy of manipulator positioning, and more seriously, the premature fatigue failure of flexible structure [8] and it could be reduced by improving the dynamic model of the system. Therefore, it is significant to conduct studies to apprehend dynamic characteristics of such system and find some structural parameter design criterion to minimize the vibration amplitude.

     In this paper, a typical flexible slender truss-structure mounted manipulator (FSTMM) for on-orbit assembly, as shown in Fig. 1(a), is studied. During the robot is assembling the truss structure, the robot is mounted on the long truss to assemble the next module of the truss. To focus on the fundamental issues of the dynamic problem, the long truss structure can be simplified as a flexible beam [3], [9] and only the first link of manipulator is considered. Such system is a typical beam–rotating link interaction system. A very limited work of such system has been reported. For example, the speed exclusion zone of a wind turbine, which was regarded as a typical cantilever beam structure attached with a rotating unbalanced mass, was investigated to prevent tower resonance [10]. The nonlinear dynamic behavior of a non-ideal unbalanced motor in a simple cantilever beam system was investigated and the results indicate there appears the jump phenomenon, namely the Sommerfeld effect [11], [12]. A model using RLC circuits with variable capacitance based on the saturation phenomenon is used to control the vibration of a hinged-hinged beam supporting unbalanced machine [13]. A nonlinear dynamical model of a robot manipulator consisting of a flexible cantilever beam and rigid second link is derived using a Lagrange equation and a Lyapunov-based feedback control law is then introduced to suppressing bending vibrations in the flexible link [14].

Conclusion

     Nonlinear dynamic of a flexible slender truss-structure mounted manipulator for on-orbit assembly, which can be simplified as a beam–rotating link interaction system, is theoretically investigated for primary and sub-harmonic resonance. The PDEs of system is established by using the D’Alembert principle incorporated with the moment balance method in which the slope of beam is considered. Such system is a typical parametrically excited system. The multiple scales method is used to solve the second-order ODEs which is reduced by the Galerkin’s method with a single mode approach from obtained PDEs. Then, the non-linear response, stability and bifurcations for primary and all sub-harmonic resonance conditions have been investigated by varying system parameters. By inspecting the results of this analysis, the following conclusions could be made:

     When the excitation frequency of manipulator ω1 near equal to the linear natural frequency of flexible truss-structure ωref , there will exist simple resonance condition and only have nontrivial steady state solution. The system resonance could be classified into monostable and bistable region by saddle-node (SN) bifurcation point. The steady state responses of the system in bistable region are determined by the initial condition and a slight change of initial conditions may cause a significant change. On the other hand, increasing the level of damping, as well as decreasing the mass of rigid manipulator and installation position of manipulator close to fixed end will reduce steady state responses of beam.

MRI is central to neurologic diagnosis and treatment planning, with a rich history of innovations drawing on knowledge and insights from clinical neuroscience experts.1–3 Recent advances in physiologic imaging, quantitative methods, informatics, artificial intelligence, and scan-time reduction are yielding more information with which to make early clinical diagnoses, but also resulting in greater complexity and the need for strong multidisciplinary communication among subspecialty professionals. At least a rudimentary technical literacy of MRI is important for all clinicians who regularly refer patients for MRI. Although there are only a few procedure codes to consider when ordering an MRI, there should be an appreciation for the clinical detail required to select from the many MRI scanning protocols, sequences, and parameters that should be tailored precisely to answer the clinical question for that individual patient.4 Furthermore, knowledge of fundamentals enables the ordering provider to ask about the availability of special techniques that may improve conspicuity of suspected pathologic condition, set expectations for the patient experience, and take advantage of readily available images to enhance shared decision making with patients. Ultimately, understanding the language of MRI permits a more successful collaboration between patient care and diagnostic imaging professionals. The purpose of this article is to provide an overview of currently available MRI capabilities, and those in the process of becoming mainstream, to help the practicing clinician achieve these goals. A complete didactic is outside of the scope possible within this article, so the reader is advised to consult readily available papers, books, videos, and illustrations for additional detail on MRI techniques5–9; safety considerations related to contrast use, implanted devices or cosmetics10–13; and appropriate utilization guidelines used by payers and regulatory agencies.

1- Prostate multiparametric magnetic resonance imaging

2- MRI interpretation

3- Limitations, challenges, and future developments

4- Conclusions

References

Abstract

Background: There is large variability among radiologists in their detection of clinically significant (cs) prostate cancer (PCa) on multiparametric magnetic resonance imaging (mpMRI). Objective: To reduce the interpretation variability and achieve optimal accuracy in assessing prostate mpMRI. Design, setting, and participants: How the interpretation of mpMRI can be optimized is demonstrated here. Whereas part 1 of the “surgery-in-motion” paper focused on acquisition, this paper shows the correlation between (ab)normal prostate anatomical structures and image characteristics on mpMRI, and how standardized interpretation according to Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) should be performed. This will be shown in individual patients. Surgical procedure: To detect csPCa, three mpMRI “components” are used: “anatomic” T2- weighted imaging, “cellular-density” diffusion-weighted imaging, and “vascularity” dynamic contrast-enhanced MRI. Measurements: Based on PI-RADS v2, the accompanying video shows how mpMRI interpretation is performed. Finally, the role of mpMRI in detecting csPCa is briefly discussed and the main features of the recently introduced PI-RADS v2.1 are evaluated. Results and limitations: With PI-RADS v2, it is possible to quantify normal and abnormal anatomical structures within the prostate based on its imaging features of the three mpMRI “components.” With this knowledge, a more objective evaluation of the presence of a csPCa can be performed. However, there still remains quite some space to reduce interobserver variability. Conclusions: For understanding the interpretation of mpMRI according to PI-RADS v2, knowledge of the correlation between imaging and (ab)normal anatomical structures on the three mpMRI components is needed. Patient summary: This second surgery-in-motion contribution shows what structures can be recognized on prostate magnetic resonance imaging (MRI). How a radiologist performs his reading according to the so-called Prostate Imaging Reporting and Data System criteria is shown here. The main features of these criteria are summarized, and the role of prostate MRI in detecting clinically significant prostate cancer is discussed briefly

Prostate multiparametric magnetic resonance imaging

Magnetic resonance imaging (MRI) is a noninvasive imaging technique that uses the interaction between radiofrequency pulses, a strong magnetic field, and body tissue, to obtain images of planes inside the body. Compared with other imaging modalities, such as ultrasound and computed tomography (CT) scanning, MRI is superior in soft tissue imaging [1]. Unlike x-rays and CT scans, MRI uses no radiation. The recommended technique of MRI in prostate cancer (PCa) is multiparametric-MRI (mpMRI), which includes high-resolution T2-weighted (T2W) images to depict prostate anatomy and two functional MRI techniques, including diffusion-weighted imaging (DWI) to display cell density and dynamic contrast-enhanced MRI (DCE-MRI) that shows vascularity. Clinical indications for mpMRI of the prostate include detection and localization of primary PCa for guidance of MRI-directed biopsy (MRDB), local staging, assessment of suspected PCa recurrence, active surveillance, and local treatment (eg, surgery, radiation therapy, and focal therapy) [2–7].

Mild cognitive impairment (MCI) represents the intermediate stage between normal cerebral aging and dementia associated with Alzheimer’s disease (AD). Early diagnosis of MCI and AD through artificial intelligence has captured considerable scholarly interest; researchers hope to develop therapies capable of slowing or halting these processes. We developed a state-of-the-art deep learning algorithm based on an optimized convolutional neural network (CNN) topology called MCADNNet that simultaneously recognizes MCI, AD, and normally aging brains in adults over the age of 75 years, using structural and functional magnetic resonance imaging (fMRI) data. Following highly detailed preprocessing, fourdimensional (4D) fMRI and 3D MRI were decomposed to create 2D images using a lossless transformation, which enables maximum preservation of data details. The samples were shuffled and subject-level training and testing datasets were completely independent. The optimized MCADNNet was trained and extracted invariant and hierarchical features through convolutional layers followed by multi-classification in the last layer using a softmax layer. A decision-making algorithm was also designed to stabilize the outcome of the trained models. To measure the performance of classification, the accuracy rates for various pipelines were calculated before and after applying the decision-making algorithm. Accuracy rates of 99.77% ± 0.36% and 97.5% ± 1.16% were achieved for MRI and fMRI pipelines, respectively, after applying the decisionmaking algorithm. In conclusion, a cutting-edge and optimized topology called MCADNNet was designed and preceded a preprocessing pipeline; this was followed by a decision-making step that yielded the highest performance achieved for simultaneous classification of the three cohorts examined.

Introduction

Cognitive impairment is a general term referring to impairments in cognition among the domains of memory, learning, concentration and decision-making. Cognitive impairment ranges from mild to severe and the symptoms can worsen over time and ultimately prevent a patient from performing daily tasks. Mild Cognitive impairment (MCI) was first utilized by Reisberg et al. [1] and is currently defined as a decline in cognitive ability that is detectable however lacking in terms of the severity to alter one’s functioning of daily living. The National Institute on Aging Alzheimer’s Association (NIA-AA) has provided criteria to diagnose dementia and MCI when there occurs a significant cognitive deterioration from an individual’s previous level [2], [3]. Additionally, research demonstrates that elderly adults with a diagnosis of MCI have a higher risk of developing dementia and age-related cognitive decline [4]. Petersen et al.’s research demonstrates that although there is still a scoring threshold in determining MCI, the memory decline of individuals with MCI is approximately1.5 standard deviations below normative data of same age and educationally matched peers [5], [6]. Gallagher et al. indicate depression and anxiety have been reported in almost 50% of individuals with MCI, and a link between depression and anxiety with cognitive decline has been found [7]–[9].

Introduction

Materials and methods

Results

Conclusion

References

Abstract

Objective
Ventriculomegaly is one of the most common anomalies encountered at obstetric ultrasound and it necessitates follow up. Fetal magnetic resonance imaging (MRI) can be used to confirm the ultrasound diagnose or to detect additional anomalies. Aim of this study is to assess follow up and management of fetal ventriculomegaly shown by ultrasound, and to evaluate additional diagnostic contribution of MRI. Study Design
This study was conducted retrospectively including 89 patients who had fetal MRI subsequent to ultrasound diagnose of ventriculomegaly in between 2011-2017. Medical records of patients were investigated and accompanying anomalies, congenital infection, chromosomal examination, degree and progression of ventriculomegaly, neonatal imaging and diagnose, and neurodevelopmental findings on follow up were evaluated. Patients were classified in two groups as isolated and nonisolated ventriculomegaly, and subgroups mild, moderate, severe were formed according to their findings. SPSS 23.0 programme was used for statistical analysis.
Results
Ultrasound and following MRI was performed in a range of 18-35th gestational weeks, diagnoses were isolated ventriculomegaly for 56 patients and nonisolated ventriculomegaly for 33 patients. Progression and neurodevelopmental delay was higher in severe nonisolated ventriculomegaly group. There was not significant contribution of MRI in the follow up of isolated ventriculomegaly (p < 0.001), and diagnostic imaging findings declined in neonatal period with proceeding normal neurodevelopment in 92.7% of patients followed with diagnosis of isolated ventriculomegaly.
Conclusion
When isolated ventriculomegaly is detected, ultrasound performed by an experienced team is mostly sufficient. MRI can be used in suspicious cases or when ventriculomegaly progresses.

Introduction

In obstetric follow up, ultrasound is the main imaging tool to monitor fetal growth and development. Technologic development and increased experience in ultrasound practice in recent years has allowed ultrasound imaging for both routin purposes and detailed fetal investigation to provide better information in management of the patient [1]. However, beyond major anomalies that can be exactly shown by detailed obstetric ultrasound including fetal neurosonogram, suspicious findings that necessitate to be clarified in the proceeding visits can also be encountered. One suchlike finding involves lateral ventricle measurement which is an important part of central nervous system evaluation. According to ISUOG (International Society of Ultrasound in Obstetrics and Gynecology) guidelines, measurement of atrial width at the level of glomus of the choroid plexus, perpendicular to the long axis of ventricle, using the inner edges of the lateral walls is recommended for ventricular measurement, and
10 mm is described as ventriculomegaly [2]. Ventriculomegaly, prevalance of which is reported to be 0.3–2%, may be unilateral or bilateral [3]. Furthermore, mild, moderate or severe forms which are defined due to measured width of lateral ventricle may be seen, although the exact definition concerning cut-off values varies at different studies [4,5]. Ventriculomegaly may regress or progress during follow up, it may also accompany other cranial or extracranial anomalies. Whether serious fetal anomalia is doubted, fetal magnetic resonance imaging (MRI), which is especially helpful for assessment of central nervous system anomalies, can be used to confirm the ultrasound diagnose or to detect additional anomalies [6]. Aim of this study is to assess follow up and management of fetal ventriculomegaly shown by detailed obstetric ultrasound, and to evaluate additional diagnostic contribution of MRI on this process.

In this paper, resonance effects in transformer windings are thoroughly investigated and analyzed. The resonance isdeterminedbymakinguse of anaccurate approachbasedonthe applicationofthe impedance matrix of a transformer winding. The method is validated by a test coil and the numerical results are verified by an ATP-EMTP model. Further analysis is applied on a transformer winding for which the inductance and the capacitance matrix as well as the winding losses are previously determined. By having determined the amplification factor, it can be found the location where the most severe transients may occur. It is also shown that maximum resonance overvoltage depends on the duration of the excitation and its resonance frequency.

Introduction

Transformers are important devices which are inevitable for the existence and the operation of power systems. The study of transient behavior of transformer voltages and currents is important for transformer designers and system planners, in order to know the interaction between the transformer and the system during different disturbances. Transformers may normally possess more resonance (natural) frequencies, which exist because transformer windings and coils can be seen as a number of series inductances and shunt capacitances. When a transformer is excited by a voltage that oscillates with a frequency equal to some of the resonance frequencies, a resonance occurs. During this process, the total winding impedance is determinedby the copper losses ofthe transformer winding.Hence, the resonance is a phenomenon in which the terminal transformer impedance is fully resistive and the imaginary impedance part is equal to zero. In this case, the total impedance becomes either minimum (series resonance) or maximum (parallel or anti-resonance). In case of a series resonance, the transformer is exposed to high overvoltages voltages, and the voltage distribution in the winding is non-linear since winding capacitances cannot be ignored. The evaluation of this distribution is important in order to know, which of the windings experience the highest stresses and under which conditions;lightning or switching. One important parameter that provides insight about voltage amplitudes along the winding is the amplification factor. This parameter was studied in Ref. [1]. During non-standard waves, resonance overvoltages may take different values. The analysis is performed to a single transformer even though the procedure is valid for multi-transformer windings as long as the impedance matrices, the elements of which are frequency dependent, are accurately determined. Nowadays different types of models are applied to study transformer transients. The powerful vector fitting model, which is very accurate belongs to the group of blackbox modeling [2]. Its application depends on the measured admittance matrices within broad frequency range. A model based on 2 port network representation by making use of a Frequency Response Analysis (FRA) is another example of an efficient black box approach [3]. Another type of models are white box models. These are numerical models that make use of inductance-, capacitance- and resistance matrices. The advantage of the white box models is that transient analysis is performed within broad frequency range. However, the disadvantage is that the accuracy strongly depends on the accuracy of computed parameters, particularly inductance and capacitance matrix as well as losses, which are frequency dependent [4–6]. Finally, the last type of models are gray box models. These models are built in EMTP-based software packages, and some transformer parameters previously determined by white box model can be tuned to the measured values (black-box). In this way, inaccuracies of white box model can be eliminated.

1.1. Pore structure of cementitious materials

On its smallest scale, cement stone is made up of hydrated calciumsilicates (C-S-H), being responsible for cohesion and strength. C-S-H forms the structural backbone and largely defines the pore structure. In this, gel pores form with sizes as small as a few nanometres. These pores strongly interact with water. Drying of gel pores leads to a shrinkage of cement stone and conversely, if empty gel pores are filled again, a swelling of the cement matrix occurs. [1–5] A currently widely adopted model developed by Jennings describes C-S-H as a lammenar [6] colloid [7] structure. This model is based on a composition of so-called globules with sizes of about 8 nm. Water is found in four different positions inside the globular C-S-H structure: (i) as so-called interlayer water between C-S-H sheets, (ii) in intraglobular pores (IGP) smaller than 1 nm, both inside the C-S-H globules, as well as (iii) in small gel pores (SGP) with sizes of about 1–3 nm and (iv) large gel pores (LGP) with sizes of 3–12 nm in interstitial spaces between globules. Within this model, large gel pores show similarities to capillary pores to some extent. IGP originate in imperfections inside the C-S-H sheets. Though being similar in size to small gel pores between globules, they largely differ in their accessibility to e.g. nitrogen, leaving voids upon emptying. In Fig. 1 a schematic representation of the pore spaces according to Jennings colloid model CM-II is drawn. The detailed nature of the on-going processes while drying and rewetting in cement stone has been a point of discussion for some time. Mostly, two different processes at drying of hardened white cement paste are distinguished [3]: (i) mesopores grow between a relative humidity1 (RH) of 95% down to 40%, accessible to both, water vapour and nitrogen and (ii) drying below 40% RH leads to the further increase of mesopore volume, interpreted as a consolidation of C-S-H structure. In the latter, differences in nitrogen and water vapour absorption are explained by nitrogen inaccessible IGP formed inside the consolidated C-S-H globules. Maruyama et al. [3] showed a temporary reduction of drying shrinkage between these processes, explained as resolution of capillary tension inside the pore structure. Similar results were obtained by Setzer and his co-workers before [4, 5]. On a slightly larger scale, capillary pores are formed by an excess of liquid water at the making as well as water emptied pore space due to chemical shrinkage and self desiccation [8]. These pores are associated with transport processes such as capillary sorption. The equations developed by Washburn [9] suggest, that sorptivity S is proportional to the porosity Φ times the square root of the overall transport effective pore radius R [10]. For simplicity, the contact angle between the wetting liquid and the pore surface α usually is set to zero, thus its influence neglected [10, 11]. The overall curvature, described by tortuosity, and the interconnection of pores, described by restrictivity, are also expected to be important influences [10].

High Voltage Power Supply encompass a broad application spectra such as analytical instruments for spectroscopy and electrophoresis, ion mass analyzers, smart material based actuators etc [1]–[4]. Analytical instruments like ion mass analyzer perform study and characterization of ions for space instrumentation systems. Such instruments comprise of electrostatic ion detector and deflector plates. The ion detector requires voltage in the range of 1.5 – 3 kV to scan and focus ions of specific energy level and is electrically modeled as a resistive load of 20 – 50 MΩ [2]. Analytical instrument employed in ozone generation require voltage in the range of 1 – 3 kV and is electrically modeled as resistive load (375 – 700 kΩ) [3]. Such devices are battery fed, operates with low power (typically in the range of 200 mW – 5 W) and need light weight high power density intermediate processing systems. A constant regulated output voltage with lower steady state ripple is required for effective operation of instruments modeled as resistive loads. To cater such requirements, numerous topologies each with distinct advantages and disadvantages are proposed in literature [5]. Flyback converters have been widely used because of their relative simplicity and their performance for power rating less than 100 W [6]. Some constructive features of the flyback converter include: isolation between the source and load side, requires a capacitive filter on the HV side, compact with low component count. Transfer of energy from source to load in a flyback converter occurs by energy storage in an intermediate flyback transformer. In HVLP flyback converters for the above applications feeding resistive loads, flyback transformers are designed with larger secondary turns and hence leads to higher self capacitance of transformer winding [7]–[9]. In general, the presence of parasitics impose a deviating behaviour in converter’s operation, in comparison with the ideal characteristic. In a flyback converter specific to HVLP applications, the primary requirement of achieving the desired steady state gain is itself restricted by the parasitic capacitances [10]. A significant energy exchange occurs between parasitic capacitance (Cef f ) and magnetising inductance (Lm) resulting in notable transition intervals apart from the typical intervals of an ideal flyback converter [11]. Converter’s operation is categorized as Continuous (CCM) or Discontinuous (DCM) based on the variations of the load. CCM operation is also known as incomplete energy transfer mode since a part of the energy drawn from the source is retained by the flyback transformer. CCM for flyback converters specific to HVLP applications poses semiconductors with higher voltage stress and results in an inefficient hard switching process. The presence of a high turns ratio transformer results in high effective capacitance (Cef f ) across drain to source of the primary active switch; this results in a significant amount of energy loss at the turn on instant of the active switch. Therefore the switching loss of the converter dominate the conduction loss.

Computed medical record database management is increasingly important as information and computer technology progress rapidly. Medical records contain treatment history and relevant experiences pertaining to the patients need to be documented accurately and efficiently. In many parts of the worlds, including Malaysia, clinical documentations are still being handwritten on forms and filed into paper medical records. The shortcomings of paper records are well identified, for example, illegibility and poorly organized records may lead to information gaps or inconsistencies, when used by another or even the same user later on. Hardcopies of documents are slow to be transferred around, with higher risk of being misplaced. In addition, when handled by multi-users in multi-locations, the quality of safekeeping can be significantly affected. [1, 2]. The advent of computer technology has introduced enormous possibilities for electronic documentation and usage of electronic medical records. The motivation of this system is to create a tailor-made computerized brain database management system for the Radiology Department of selected hospitals in Malaysia. This is achieved by studying the existing system and its problems, and then designed an appropriate database system. The work flow of the old filing system is first to create record, on which the diagnosis and treatment report are documented by various personnel. The report is then filed and stored in the department. This is repeated until the patient is discharged, where the record is then taken out and stored in the Medical Record Unit of the hospital. With respect to the scanning records, the medical images are also stored in the paper folder record. After the installation of the new system, the database will be used to deduce certain useful information about the brain infarction patients in the hospital. In Malaysia, stroke is the main cause of mortality and morbidity, after heart disease and cancer. Stroke is a multiple factorial disease regulated by modifiable and non-modifiable risk factors. Modifiable factors include a history of hypertension, diabetes mellitus, obesity, smoking and obstructive sleeping apnea syndrome. Nonmodifiable factors include age, sex and race. Stroke is known as a cerebrovascular accident (CVA), which is rapidly developing loss of brain function due to disturbance in the blood supply to the brain. Ischemia caused by blockage, or a hemorrhage is known as the common reason for stroke [3]. On brain imaging method, computed tomography (CT) and magnetic resonance imaging (MRI) are the most commonly imaging methods used in Malaysia. MRI has proven to have a better reliability and sensitivity than CT in brain imaging, and it is a proven research and diagnostic tool. However, CT scan is also widely available, being fast, easy, and less expensive than MRI [4 – 7].

Marketers attempt to cultivate and leverage brand-centric relationships with key stakeholders in order to enhance the equity of their respective brands (e.g., Fournier, 1998; Keller, 2013). Brand resonance refers to the nature of heightened brand-centric relationships that transcend mere product or service dimensions to include deep psychological attachments and active supportive behaviors directed toward the focal brand (Fournier, 1998; Keller, 2013; Thomson, MacInnis, & Park, 2005). Keller (2013, p.92, italics in original) describes brand resonance “in terms of intensity, or the depth of psychological bond that customers have with the brand, as well as the level of activity engendered by this loyalty.” The cultivation of brand resonance, therefore, has the potential to enhance the success of marketing programs in both business-to-consumer and business-to-business contexts. In franchising relationships, where alliances between franchisors and franchisees are formed using brands as the foundation, brand resonance among franchisees holds tremendous importance for the equity of the franchised brand. Both franchisors and franchisees share the responsibility for promoting and sustaining the equity of the franchised brand (Nyadzayo, Matanda, & Ewing, 2011) and, although neither party has complete control over the brand management process, they are mutually dependent on one another to safeguard the identity and image of the franchised brand (Pitt, Napoli, & Van Der Merwe, 2003).

مقاله سال 2017

مقاله سال 2016

 مجله تحقیقات بازاریابی – Journal of Business Research

Marketers attempt to cultivate and leverage brand-centric relationships with key stakeholders in order to enhance the equity of their respective brands (e.g., Fournier, 1998; Keller, 2013). Brand resonance refers to the nature of heightened brand-centric relationships that transcend mere product or service dimensions to include deep psychological attachments and active supportive behaviors directed toward the focal brand (Fournier, 1998; Keller, 2013; Thomson, MacInnis, & Park, 2005). Keller (2013, p.92, italics in original) describes brand resonance “in terms of intensity, or the depth of psychological bond that customers have with the brand, as well as the level of activity engendered by this loyalty.” The cultivation of brand resonance, therefore, has the potential to enhance the success of marketing programs in both business-to-consumer and business-to-business contexts.

In franchising relationships, where alliances between franchisors and franchisees are formed using brands as the foundation, brand resonance among franchisees holds tremendous importance for the equity of the franchised brand. Both franchisors and franchisees share the responsibility for promoting and sustaining the equity of the franchised brand (Nyadzayo, Matanda, & Ewing, 2011) and, although neither party has complete control over the brand management process, they are mutually dependent on one another to safeguard the identity and image of the franchised brand (Pitt, Napoli, & Van Der Merwe, 2003).

For instance, franchisors are responsible for building the equity of their brand within the franchising network as well as among end-consumers (Davis & Mentzer, 2008). On the other hand, franchisees are key brand contacts for consumers and bear responsibility for reflecting the franchised brand’s meaning consistently as well as influencing consumer attitudes and behaviors toward the brand (Gould, 2005; Leiser, 2012). When franchisees develop strong relationships with the franchised brand, they are more likely to surpass contractually specified behaviors and volitionally engage in actions that enhance the brand’s value (Nyadzayo et al., 2011). However, although prior research has focused extensively on brand relationships in consumer and business contexts (e.g., Fournier, 1998; Keller, 2013; Kotler & Pfoertsch, 2007), very little is known about the cultivation of brand-centric relationships among franchisees and, specifically, the drivers of brand resonance in franchising networks (Nyadzayo et al., 2011).