The media industry has during the last decade migrated services from dedicated medianetworks to more shared resources and lately also the public internet and public data centers. Inorder to cater for such transition, several protocols have been designed to meet the demand forhigh-quality media transport over lossy infrastructure, protocols such as SRT and RIST. Thepurpose of Reliable Internet Stream Transport (RIST) and Secure Reliable Transport (SRT) is tohave all vendors of broadcasting equipment support an interoperable way of communication. Thelack of interoperability locks consumers into one particular vendor’s family of products - most oftenthis equipment only supports a proprietary technology. Interoperability creates a more competitivemarket space which benefits consumers and gives vendors an incentive to be more innovative intheir solutions. The purpose of this thesis is to assess the performance of these protocols by comparing theirperformance to a proprietary solution (named ÖÖÖ in this thesis and seen as an establishedsolution in the industry). The challenge is to test these protocols in a lab environment, but have theresults represent real-world use. For this, a large subset of samples is needed along with samplesmeasured over a long period. This sampling was made possible by writing a script which automatesthe sampling process. The results indicate that the versions of RIST and SRT tested in this thesis to some extentcompare well to the selected established protocol (ÖÖÖ). In many scenarios, SRT even did muchbetter, mainly when a line with a single feed was tested. For instance, when the network suffered a2% drop rate and utilized retransmission SRT performed the best and was the only protocol whichhad some samples where no packets were dropped during one hour of measurements. Whenrunning all three protocols at the same time, SRT also did the best in a network with up to 12% droprate. The results in this thesis should give a broadcaster an idea of which of these protocols willfulfill their requirements in a broadcast application. / I mediabranschen finns det en efterfrågan på utrustning som har inslag av interoperabilitet.Anledningen till detta är att någon som köper produkter från en viss återförsäljare inte vill låsas in idenna återförsäljares ”ekosystem” i flera år framöver. Då en studio sällan uppgraderar hela sinproduktionskedja på samma gång ger interoperabilitet möjligheten att köpa utrustning från andraåterförsäljare när man ska uppgradera något i produktionslinan. Detta leder till en merkonkurrenskraftig marknad samt ger incentiv till nya innovativa lösningar. Detta examensarbete går ut på att utvärdera lösningar som tagits fram för att främjainteroperabilitet och jämföra dem med en existerande proprietärlösning. Reliable Internet StreamTransport (RIST) och Secure Reliable Transport (SRT) är två protokoll som tagits fram för just dettasyfte. Utmaningen med att utvärdera dessa protokoll är att i en labbmiljö få resultat som reflekteraranvändandet av protokollen i verkligheten. Detta har gjorts med hjälp av ett program som tagitsfram i detta examensarbete. Med detta program har testandet kunnat automatiseras. Resultaten i detta examensarbete visar potential hos båda RIST och SRT. SRT är i vissascenarion till och med bättre än den proprietära lösningen. Protokollen visar något buggigtbeteende i vissa instanser, såsom att i vissa fal sluta fungera och inte kunna återgå till normalfunktion utan manuell interaktion. Allt som allt är dock protokollen i de flesta fallen testade i dettaexamensarbete ett godtyckligt alternativ till den jämförda proprietära lösningen.

This Thesis is an embodiment of some research work carried out towards achieving faster and more reliable handover techniques in a Mobile WiMAX (Worldwide Interoperability for Microwave Access) network. Handover, also called handoff, is the critical mechanism that allows an ongoing session in a cellular mobile network like WiMAX to be seamlessly maintained without any call drop as the Mobile Station (MS) moves out of the coverage area of one base station (BS) to that of another. Mobile WiMAX supports three different types of handover mechanisms, namely, the hard handover, the Fast Base Station Switching (FBSS) and the Micro-Diversity Handover (MDHO). Out of these, the hard handover is the default handover mechanism whereas the other two are the optional schemes. Also, FBSS and MDHO provide better performance in comparison to hard handover, when it comes to dealing with the high-speed multimedia applications. However, they require a complex architecture and are very expensive to implement. So, hard handover is the commonly used technique accepted by the mobile broadband wireless user community including Mobile WiMAX users. The existing Mobile WiMAX hard handover mechanism suffers from multiple shortcomings when it comes to providing fast and reliable handovers. These shortcomings include lengthy handover decision process, lengthy and unreliable procedure of selecting the next BS, i.e., the target BS (TBS) for handover, occurrence of frequent and unwanted handovers, long connection disruption times (CDT), wastage of channel resources, etc. Out of these, reducing the handover latency and improving the handover reliability are the two issues that our present work has focused on. While the process of selecting the TBS for handover adds to the overall delay in completing the process of handover, choosing a wrong TBS for handover increases the chance of further unwanted handovers to occur or even a call drop to occur. The latter greatly hampers the reliability of a handover. In order to contribute to the solution of the above two problems of slow handover and unreliable handover, this Thesis proposes and investigates three handover techniques, which have been called Handover Techniques 1, 2 and 3, respectively. Out of these three techniques, the first two are fully MS-controlled while the third one is a dominantly serving BS-controlled. In Handover Techniques 1 and 2, which share between them some amount of commonness of ideas, the MS not only itself determines the need for a handover but also self-tracks its own independent movement with respect to the location of the (static) neighboring BSs (NBS). N both these handover techniques, the MS performs distance estimation of the NBSs from the signal strength received from the NBSs. But they (the two handover techniques) employ different kinds of “lookahead” techniques to independently choose, as the TBS, that NBS to which the MS is most likely to come nearest in the future. Being MS-controlled, both Handover Technique 1 and Handover Technique 2 put minimal handover-related workload on their respective SBSs who thus remain free to offer services to many more MSs. This interesting capability of the two handover techniques can increase the scalability of the WiMAX network considerably. In Handover Technique 3, which is a BS-controlled one with some assistance received from the MS, the SBS employs three different criteria or parameters to select the TBS. The first criterion, a novel one, is the orientation matching between the MS’s direction of motion and the geolocation of each NBS. The other two criteria are the current load of each NBS (the load provides an indication of a BS’s current QoS capabilities) and the signal strength received by the MS from each NBS. The BS assigns scores to each NBS against each of the three independent parameters and selects the TBS, which obtains the highest weighted average score among the NBSs. All three handover techniques are validated using simulation methods. While Handover Techniques 1 and 2 are simulated using Qualnet network simulator, for Handover Technique 3, we had to design, with barest minimum capability, our own simulation environment, using Python. Results of simulation showed that for Handover Techniques 1 and 2, it is possible to achieve around 45% improvement (approx) in the overall handover time by using the two proposed handover techniques. The emphasis in the simulation of the Handover Technique 3 was on studying its reliability in producing correct handovers rather than how fast handovers are. Five different arbitrary pre-defined movement paths of the MS were studied. Results showed that with orientation matching or orientation matching together with signal strength, reliability was extremely good, provided the pre-defined paths were reasonably linear. But reliability fell considerably when relatively large loads were also considered along with orientation matching and signal strength. Finally, the comparison between the proposed handover techniques in this Thesis and few other similar techniques in Mobile WiMAX proposed by other researchers showed that our techniques are better in terms providing fast, reliable and intelligent handovers in Mobile WiMAX networks, with scalability being an added feature.

隨著網路的進步與發展，許多新興的資訊服務，如影音資訊，在網路上傳輸時並未要求封包都送達，不同的封包有不同的重要性，例如 MPEG的關鍵畫面(I -Frame)就比其他畫面重要。常用的傳輸層通訊協定中，UDP與TCP都對所有的封包一視同仁，前者不做任何保證，而後者雖可保證所有封包的送達，但效率較差。 本研究提出一個新的TCP，”Partial-Reliable TCP”，使用選擇性重傳機制，配合應用程式的需求，對指定的封包提供遞送保護。當封包遺失時，只重傳保護的封包，可減少額外的網路資源消耗，並提升服務的品質。 此外，我們提出Single-Side的版本，接收端可以使用一般的 TCP，在封包傳送時，讓接收端以為封包都是無誤傳達的，在server-client架構的網路服務中，只有伺服器端必須使用我們的Partial-Reliable TCP，大幅提高本通訊協定的可行性。 最後我們利用網路模擬工具NS-2來模擬實際網路環境，將我們的方法與現行的通訊協定在可解畫面封包數、PSNR值及額外耗用的網路資源三個參數做比較。我們使用兩個 Video 影像作為傳輸標的，在高遺失率的有線與無線網路的環境中進行實驗。當傳輸時間限制很短時，（例如影像會議的應用），在有線的環境中， Basic PR-TCP比TCP Reno、TFRC最少增加約18%的可解畫面封包數，比UDP、TFRC及TCP Reno的PSNR值最少高出約15%，比TCP Reno及TFRC最少節省了12%的頻寬資源，Single-Side PR-TCP比Basic PR-TCP的PSNR值約低了11%，額外耗用的頻寬約多出10%。在無線的環境中，Basic PR-TCP比TCP Reno、TFRC最少增加約19%的可解畫面封包數，比UDP、TFRC及TCP Reno的PSNR值最少高出約20%，比Single-Side PR-TCP、TCP Reno及TFRC最少節省了15%的頻寬資源，Single-Side PR-TCP比Basic PR-TCP的PSNR值約低了14%。當傳輸時間限制較充裕時 (例如VoD應用)，Basic PR-TCP雖然比TCP Reno及TFRC降低了約3%的PSNR值，但是最少能節省8%的頻寬耗費，Single-Side PR-TCP的PSNR值跟Basic PR-TCP相近，但是額外耗用約5%的頻寬資源。 / With the advance of computer and communication networks, many new information services over IP-based networks such as video streaming and VoIP (Voice over IP) are growing rapidly. These services can tolerate some packets lost in transmission without too much damage to their quality. The content carried in the packets of these services is not equally important in their replay processes. For example, key frames (e.g. I-Frames) of a video encoded in MPEG format are more important than others. The loss of I-frames may have a large impact to the quality of the transmitted video, while the loss of other types of frames may only have nominal damage. Unfortunately, the two most popular transport protocols, UDP and TCP, treat all packets equally without any discrimination. TCP guarantees the delivery of all packets, while UDP doesn't. TCP may waste too much resource to guarantee the delivery of unimportant packets, while UDP may fail to deliver too many important packets. This thesis proposes a new TCP protocol, named Partial-Reliable TCP (PR-TCP), which applies selective retransmission strategy to provide delivery guarantee to the selected packets designated by the application programs. In this way, we can save bandwidth consumption and reduce the average delivery time without significant quality degradation. In fact, if the delivery of an object requires a stringent delivery time, the reduction of average delivery time may also lead to the reduction of abandoned packets at the receiver end. We propose two different versions of PR-TCP, Basic PR-TCP and Single-Side PR-TCP. Basic PR-TCP requires both ends of a connection to adopt PR-TCP while Single-Side PR-TCP only requires the sender end to adopt it. It is much easier to deploy Single-Side PR-TCP on the client-server systems where only servers need to use PR-TCP. Finally, we use NS-2 network simulator to evaluate our PR-TCP against TCP Reno, TFRC and UDP. Two video stream samples are used for video sources. Three quality parameters are evaluated: wasted bandwidth consumption, PSNR, and the number of packets in decodable frames. Under heavy loaded wired network and short delay bound (<0.8 sec.), the simulation shows that Basic PR-TCP can outperform TCP Reno and TFRC in the number of packets in decodable frames by at least 18%. It can outperform TCP Reno, TFRC, and UDP in PSNR by at least 12%. The performance of Single-Side PR-TCP is less then Basic PR-TCP in terms of PSNR by 10%, and it consumes larger bandwidth by 8%. Under wireless environments where error rate is high, the simulation shows that Basic PR-TCP can outperform TCP Reno and TFRC in the number of packets in decodable frames by at least 19% as well as wasted transmission overhead by at least 15%. It can also outperform TCP Reno, TFRC, and UDP in PSNR by at least 20%. The performance of Single-Side PR-TCP is less then Basic PR-TCP in terms of PSNR by 14%, and it consumes larger bandwidth by 10%. Under large delay bound (>8 sec.), the quality (PSNR) of the video transmitted using Basic PR-TCP is downgraded by only 3%, while it can save network bandwidth by 8%. The performance of Single-Side PR-TCP is about the same as Basic PR-TCP in terms of PSNR, but it consumes slightly larger bandwidth by 5%.

In this thesis, a retail market mechanism that provides differentiated reliability services is proposed. The differentiated reliability services beyond the standard level utilize advanced metering infrastructure, automated distribution reconfiguration and distributed generation (DG). The service quality at the standard level is regulated, while high reliability services are offered through a market mechanism. This proposed market mechanism is designed in two different models of managing the distribution networks. The first model assumes that an independent distribution system operator (DSO) as an administrative firm provides operational support for delivery and reliability services in a retail market, while the second model does not have a DSO. Main reliability market participants are distribution utilities, retail electricity providers (REPs), non-utility-owned DG units, and end users. The REPs, as end users’ representatives and aggregators, purchase delivery service with high reliability level and backup power from the utilities and DG units, respectively. The prices for these services are based on bidding by all market participants. Bids are created by each market participant optimizing its objective with respect to its own interests; therefore, the market participant can assess the investment costs and manage its own risk in setting the service charge. Notably, the proposed market mechanism, which is based on knowing customers’ willingness to pay, and preferences for reliability, aims to give long-term investment signals to service providers for planning investments in new technologies at value. In addition, the provision of high reliability services can be considered a means that enables the service providers to improve system resilience. The modified IEEE Roy Billinton Test System Bus 2 is simulated to demonstrate proof-of-concept for the proposed retail market by showing the iii process of settling the service prices and utilities’ expected compensation design. By comparing the settled service prices between the two market models, we show that the service prices are quite similar, but the number of end users obtaining backup power is different.

The Internet of Things (IoT) has the vision to interconnect everything of the physical world and the virtual world. Advanced automated and adaptive connectivity of objects, systems, and services is expected to be achieved under the IoT context, especially in the industrial environment. Industry 4.0 with the goal of intelligent and self-adaptable manufacturing is driven by the IoT. The Object Layer, where real-time and reliable information acquisition from the physical objects carried out, is the basic enabler in the 3-layer industrial IoT system. Such acquisition system features deterministic access, reliable communication with failure resistance mechanism, latency-aware real-time response, deployable structure/protocol, and adaptive performance on various QoS demands. This thesis proposes a reliable RFID communication system for acquisition in the industrial environment. A discrete gateway structure and a contention-free communication protocol are designed to fulfill the unique system requirements. Such gateway structure offers a flexible configuration of readers and RF technologies. It enables a full duplex communication between the objects and the gateway. The designed MF-TDMA protocol can enhance the failure resistance and emergency report mechanism thanks to the separation of control link and data link in the gateway. Specifically, an optional ARQ mechanism, an independent/uniform synchronization and control method, and a slot allocation optimization algorithm are designed besides time-division and frequency-division multiplexing. Protocol implementations for different industrial situations illustrate the system ability for supporting the demands of various QoS. Finally, a 2.4-GHz/UWB hybrid positioning platform is explored based on the introduced RFID system. Taking advantage of the UWB technology, the positioning platform can achieve positioning accuracy from meter level to centimeter level. Hybrid tag prototype and specific communication process based on the MF-TDMA protocol are designed. An SDR UWB reader network, capable of evaluating multiple algorithms, is built to realize accurate positioning with an improved algorithm proposed. / <p>QC 20161109</p>

A mobile wireless ad hoc network (MANET) consists of a group of mobile nodes communicating wirelessly with no fixed infrastructure. Each node acts as source or receiver, and all play a role in path discovery and packet routing. MANETs are growing in popularity due to multiple usage models, ease of deployment and recent advances in hardware with which to implement them. MANETs are a natural environment for multicasting, or group communication, where one source transmits data packets through the network to multiple receivers. Proposed applications for MANET group communication ranges from personal network apps, impromptu small scale business meetings and gatherings, to conference, academic or sports complex presentations for large crowds reflect the wide range of conditions such a protocol must handle. Other applications such as covert military operations, search and rescue, disaster recovery and emergency response operations reflect the "mission critical" nature of many ad hoc applications. Reliable data delivery is important for all categories, but vital for this last one. It is a feature that a MANET group communication protocol must provide. Routing protocols for MANETs are challenged with establishing and maintaining data routes through the network in the face of mobility, bandwidth constraints and power limitations. Multicast communication presents additional challenges to protocols. In this dissertation we study reliability in multicast MANET routing protocols. Several on-demand multicast protocols are discussed and their performance compared. Then a new reliability protocol, R-ODMRP is presented that runs on top of ODMRP, a well documented "best effort" protocol with high reliability. This protocol is evaluated against ODMRP in a standard network simulator, ns-2. Next, reliable multicast MANET protocols are discussed and compared. We then present a second new protocol, Reyes, also a reliable on-demand multicast communication protocol. Reyes is implemented in the ns-2 simulator and compared against the current standards for reliability, flooding and ODMRP. R-ODMRP is used as a comparison point as well. Performance results are comprehensively described for latency, bandwidth and reliable data delivery. The simulations show Reyes to greatly outperform the other protocols in terms of reliability, while also outperforming R-ODMRP in terms of latency and bandwidth overhead.

[pt] A confiabilidade metrológica dos equipamentos da cadeia de frio para conservação de produtos hemoterápicos é fundamental para garantir a eficiência de tratamentos e evitar a ocorrência de eventos adversos. Os freezers utilizados para conservação do sangue e hemocomponentes devem atender aos requisitos exigidos pela Portaria número 1.353, publicada em junho de 2011 pelo Ministério da Saúde, dentre os quais a garantia da uniformidade da distribuição de temperatura por todo o volume de armazenamento. No entanto, tal conformidade é avaliada a partir da medição da temperatura em um único ponto. No presente trabalho foi desenvolvido um sistema multicanal, com oito transdutores do modelo Pt-100, para avaliação da distribuição espacial e estabilidade temporal da temperatura em equipamentos da cadeia de frio. Foram realizadas medições da temperatura utilizando o sistema desenvolvido no volume interno de freezers de diferentes marcas, em uso para conservação de hemoterápicos, pertencentes a um serviço de hemoterapia localizado no Rio de Janeiro. Os resultados indicaram não uniformidade de distribuição espacial e temporal da temperatura no interior dos equipamentos avaliados, sugerindo a necessidade de maior abrangência do requisito para avaliação da conformidade dos equipamentos da cadeia de frio utilizados na conservação do sangue e hemocomponentes. / [en] The metrological reliability of cold chain equipment for storage of haemotherapic products is essential to ensure effective treatment and prevent the occurrence of adverse events. The freezers used for storage of blood and blood products must meet the requirements of the Ordinance number 1353, published in June 2011 by the Ministry of Health, among them the assurance of uniformity of temperature distribution throughout the storage volume. However, such compliance is evaluated from the measurement on a single point. In this study we developed a multichannel system with eight transducers Pt-100 model, to evaluate the spatial distribution and temporal stability of temperature in the cold chain equipment. Temperature measurements were performed using the system developed in the internal volume of different brands of freezers in use for conservation haemotherapic belonging to a transfusion service located in Rio de Janeiro. The results showed no uniformity of spatial and temporal distribution of temperature inside the equipment evaluated, suggesting the need for greater coverage of the requirement for conformity assessment of cold chain equipment used for the preservation of blood and blood products.

[pt] A Tomografia por Coerência Óptica (OCT) vem sendo utilizada desde a década de 1990 em diversas áreas do campo biomédico, uma biópsia óptica com importantes perspectivas como ferramenta diagnóstica para caracterização quantitativa de estruturas teciduais.No presente trabalho é realizado estudo dos parâmetros para avaliação de conformidade dos equipamentos optoeletrônicos para aplicação biomédica como Laser, IPL(Luz Pulsada Intensa) e OCT, objetivando a identificação dos itens cuja avaliação é necessária como requisito em futura norma específica para equipamentos de Tomografia por Coerência Óptica. Além dos parâmetros metrológicos requeridos na norma particular para equipamentos a Laser, e alguns dos parâmetros da norma para IPL, foram identificados outros parâmetros metrológicos específicos para avaliação de equipamentos de OCT, considerando sua aplicação biomédica, como comprimento de coerência, resolução axial e resolução transversal. Considerando a possibilidade de elaboração futura de norma específica para OCT, para alguns dos parâmetros identificados, recomendou-se o requisito de medição e, para outros, somente a inclusão da informação nos documentos acompanhantes. Dentre os parâmetros cujo requisito de medição foi recomendado para equipamentos de OCT são: potência da emissão eletromagnética, comprimento de onda central, concentricidade entre os feixes de trabalho e de mira, diâmetro e divergência do feixe de trabalho, duração de um pulso, número de pulsos em um trem de pulsos e irradiância espectral. / [en] Optical Coherence Tomography has been proving to be an efficient diagnostics technique for imaging in vivo tissues, an optical biopsy with important perspectives as a diagnostics tool for quantitative characterization of tissue structures.The present work studies the parameters conformity evaluation of optoelectronics equipment for biomedical applications like Laser, IPL (Intense Pulsed Light), and OCT, targeting the identification of items which are necessary as a requirement to develop a future specific standard for Optical Coherence Tomography equipments. Beside the metrological parameters required by the particular standard for Laser and IPL equipment, specific parameters necessary for OCT’s evaluation have been identified, regarding its biomedical application. For some parameters identified, measurement requisite has been recommended, and for others, only the information on the accompanying documents. Among the parameters required for measurement, highlights for: electromagnetic emission power, measurement uncertainty of incident power, coherence length, work beam diameter and divergence, pulse duration and spectral irradiance.

When data are stored in different locations and pooling of such data is not allowed, there is an informational loss when doing predictive modeling. In this thesis, a new method called Non-Disclosed Conformal Prediction (NDCP) is adapted into a regression setting, such that predictions and prediction intervals can be aggregated from different data sources without interchanging any data. The method is built upon the Conformal Prediction framework, which produces predictions with confidence measures on top of any machine learning method. The method is evaluated on regression benchmark data sets using Support Vector Regression, with different sizes and settings for the data sources, to simulate real life scenarios. The results show that the method produces conservatively valid prediction intervals even though in some settings, the individual data sources do not manage to create valid intervals. NDCP also creates more stable intervals than the individual data sources. Thanks to its straightforward implementation, data owners which cannot share data but would like to contribute to predictive modeling, would benefit from using this method.

School reform programs focus on making educational changes; however, research on interventions past the funded implementation phase to determine what was sustained is rarely done (Beery, Senter, Cheadle, Greenwald, Pearson, et al., 2005). This study adds to the research on sustainability by determining what instructional practices, if any, of the Teaching SMART[reg] professional development program that was implemented from 2005-2008 in elementary schools with teachers in grades third through eighth were continued, discontinued, or adapted five years post-implementation (in 2013). Specifically, this study sought to answer the following questions: What do teachers who participated in Teaching SMART[reg] and district administrators share about the sustainability of Teaching SMART[reg] practices in 2013? What teaching strategies do teachers who participated in the program (2005-2008) use in their science classrooms five years post-implementation (2013)? What perceptions about the roles of females in science, technology, engineering, and mathematics (STEM) do teachers who participated in the program (2005-2008) have five years later (2013)? And, What classroom management techniques do the teachers who participated in the program (2005-2008) use five years post implementation (2013)? A mixed method approach was used to answer these questions. Quantitative teacher survey data from 23 teachers who participated in 2008 and 2013 were analyzed in SAS v. 9.3. Descriptive statistics were reported and paired t-tests were conducted to determine mean differences by survey factors identified from an exploratory factor analysis, principal axis factoring, and parallel analysis conducted with teacher survey baseline data (2005). Individual teacher change scores (2008 and 2013) for identified factors were computed using the Reliable Change Index statistic. Qualitative data consisted of interviews with two district administrators and three teachers who responded to the survey in both years (2008 and 2013). Additionally, a classroom observation was conducted with one of the interviewed teachers in 2013. Qualitative analyses were conducted following the constant comparative method and were facilitated by ATLAS.ti v. 6.2, a qualitative analysis software program. Qualitative findings identified themes at the district level that influenced teachers' use of Teaching SMART[reg] strategies. All the themes were classified as obstacles to sustainability: economic downturn, turnover of teachers and lack of hiring, new reform policies, such as Race to the Top, Student Success Act, Common Core State Standards, and mandated blocks of time for specific content. Results from the survey data showed no statistically significant difference through time in perceived instructional practices except for a perceived decrease in the use of hands-on instructional activities from 2008 to 2013. Analyses conducted at the individual teacher level found change scores were statistically significant for a few teachers, but overall, teachers reported similarly on the teacher survey at both time points. This sustainability study revealed the lack of facilitating factors to support the continuation of reform practices; however, teachers identified strategies to continue to implement some of the reform practices through time in spite of a number of system-wide obstacles. This sustainability study adds to the literature by documenting obstacles to sustainability in this specific context, which overlap with what is known in the literature. Additionally, the strategies teachers identified to overcome some of the obstacles to implement reform practices and the recommendations by district level administrators add to the literature on how stakeholders may support sustainability of reform through time.