Computational design has become a predominant element of various engineering tasks. However, the ever increasing complexity of numerical models creates the need for efficient methodologies. Specifically, computational design under uncertainties remains sparsely used in engineering settings due to its computational cost. This dissertation proposes a coherent framework for various branches of computational design under uncertainties, including model update, reliability assessment and reliability-based design optimization. Through the use of machine learning techniques, computationally inexpensive approximations of the constraints, limit states, and objective functions are constructed. Specifically, a novel adaptive sampling strategy allowing for the refinement of any approximation only in relevant regions has been developed, referred to as generalized max-min. This technique presents various computational advantages such as ease of parallelization and applicability to any metamodel. Three approaches tailored for computational design under uncertainties are derived from the previous approximation technique. An algorithm for reliability assessment is proposed and its efficiency is demonstrated for different probabilistic settings including dependent variables using copulas. Additionally, the notion of fidelity map is introduced for model update settings with large number of dependent responses to be matched. Finally, a new reliability-based design optimization method with local refinement has been developed. A derivation of sampling-based probability of failure derivatives is also provided along with a discussion on numerical estimates. This derivation brings additional flexibility to the field of computational design. The knowledge acquired and techniques developed during this Ph.D. have been synthesized in an object-oriented MATLAB toolbox. The help and ergonomics of the toolbox have been designed so as to be accessible by a large audience.

Submitted by M?rden L?les (marden.inacio@ufvjm.edu.br) on 2016-07-21T18:35:27Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Diego_dos_Santos_Vieira.pdf: 3296114 bytes, checksum: b738df6d293269169107da9a2300aaa3 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2016-07-22T17:07:03Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Diego_dos_Santos_Vieira.pdf: 3296114 bytes, checksum: b738df6d293269169107da9a2300aaa3 (MD5) / Made available in DSpace on 2016-07-22T17:07:03Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Diego_dos_Santos_Vieira.pdf: 3296114 bytes, checksum: b738df6d293269169107da9a2300aaa3 (MD5) Previous issue date: 2015 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Objetivou-se nesta pesquisa investigar a estrutura e padr?o espacial de uma ?rea de floresta periodicamente inund?vel e suas esp?cies dominantes, de modo a contribuir para defini??o de estrat?gias de manejo e conserva??o (?rea I); analisar a estrutura diam?trica, padr?o espacial e m?todos de amostragem para estimar a densidade de Bertholletia excelsa Bonpl. na Regi?o do Baixo Rio Tapaj?s (?rea II). A ?rea I trata-se de um t?pico fragmento de Floresta Ombr?fila Densa Aluvial utilizado para atender os objetivos do cap?tulo 2, enquanto que a ?rea II representa uma Floresta Ombr?fila Densa de Terra Firme utilizada para atingir os objetivos do cap?tulo 3. Na ?rea I foram instaladas 308 unidades amostrais cont?guas de 10 x 10 m, perfazendo uma ?rea amostral de 3,08 ha. Nessas unidades amostrais, todos os indiv?duos com di?metro a 1,30 m de altura do solo (dap) ? 10 cm foram medidos, identificados e referenciados em coordenadas cartesianas (X,Y). Foram calculados os par?metros fitossociol?gicos de densidade, frequ?ncia, domin?ncia e posi??o sociol?gica, e as esp?cies ordenadas segundo o valor de import?ncia ampliado (VIA). A diversidade e o padr?o espacial foram obtidos atrav?s do ?ndice de Shannon-Weaver e fun??o K de Ripley, respectivamente. Na ?rea II, realizou-se um invent?rio de prospec??o com mapeamento de todas as ?rvores de Bertholletia excelsa Bonpl. com dap ? 20 cm, totalizando 1.000 hectares. Para an?lise da estrutura diam?trica foram utilizadas t?cnicas multivariadas: an?lise de agrupamento e discriminante. Utilizaram-se para an?lise de agrupamento a dist?ncia euclidiana e o m?todo de Ward. O padr?o espacial foi definido por meio do emprego da fun??o univariada K de Ripley. Constatado o padr?o espacial, dividiu-se o mapa em unidades de 50 x 50 m, no qual foram simulados diferentes procedimentos de amostragem (Amostragem Casual Simples, Amostragem Sistem?tica e Amostragem Adaptativa em Cluster) com intensidade amostral de 15% e limite de erro de 10%. As compara??es entre os m?todos foram realizadas por meio do teste F de Graybill e an?lises da precis?o e exatid?o obtidas das 30 simula??es realizadas para cada procedimento. Na ?rea I foram registrados 1.022 indiv?duos, distribu?dos em 64 esp?cies arb?reas e 33 fam?lias. A diversidade registrada foi de 3,03 nats.ind-1. As seis esp?cies de maior VIA foram: Campsiandra laurifolia Beth., Hevea brasiliensis (Willd. ex A.Juss.) Mull.Arg, Glicoxylon pedicellatum Ducke, Tetragastris altissima (Aubl.) Swart, Vantanea parviflora Lam. e Mabea caudata Pax & K.Hoffm. O padr?o espacial da comunidade variou em fun??o da dist?ncia considerada, por?m foi predominantemente agregado. Os padr?es espaciais detectados para as esp?cies foram: predominantemente aleat?rio para a esp?cie Vantanea parviflora; completamente agregado para as esp?cies Hevea brasiliensis e Glicoxylon pedicellatum; predominantemente agregado para Campsiandra laurifolia, Tetragastris altissima e Mabea caudata. Na ?rea II, a distribui??o diam?trica de Bertholletia excelsa apresentou clara tend?ncia ? normalidade, enquanto que o padr?o espacial foi predominantemente aleat?rio. Os m?todos de amostragem adaptativos foram ineficiente e subestimam o n?mero de indiv?duos por hectare. Os procedimentos casual simples e sistem?tico podem ser utilizados para invent?rios florestais de Bertholletia excelsa desde que haja um aumento na intensidade amostral para valores acima de 44% da ?rea total. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2015. / ABSTRACT The aim of this research was to investigate the structure and space pattern of a periodically floodable forest area and its prevalent species, in such a way to contribute to the definition of handling and conservation strategies (Area I); analyze the diameter structure, spatial pattern and sampling methods to estimate the Bertholletia excelsa Bonpl density in the Lower Tapaj?s River Region (Area II). Area I is a typical fragment of alluvial Dense Ombrophilous Forest used to accord the objectives of chapter 2, while Area II represent a Solid Ground Dense Ombrophilous Forest used to reach the aims of chapter 3. In Area I 308 contiguous sampling units measuring 10 x10 cm were installed, making a sampling area of 3.08ha. In those sampling units, all the individuals with 1.3m height from the soil (dap) > 10cm were measured, identified and referenced in Cartesian coordinates (X,Y). The phytossociological parameters of density, frequency, dominance and sociological position were calculated, and the species were sorted according to the increased importance rate (VIA). The diversity and the spatial pattern were obtained through the index of Shannon-Weaver and K function of Ripley, respectively. In Area II, an inventory of prospection with the mapping of all Bertholletia excels Bonpl. trees with dap > 20cm was made, totalizing 1,000 hectares. For the analysis of the diametrical structure multi-varied techniques were adopted: grouping analysis and discriminating analysis. To the grouping analysis the Euclidian distance and the Ward method were used. The spatial pattern was defined by employing the univariate Ripley K function. After confirming the spatial pattern, the map was divided into 50 x 50 cm units, in which different sampling procedures were simulated (Simple Casual Sampling, Systematic Sampling and Cluster Adaptive Sampling) with 15% sampling intensity and 10 % error limit. The comparisons between the methods were performed by means of Graybill F test and precision analysis obtained from the 30 simulations performed for each procedure. In Area I 1,022 individuals were recorded, they were distributed into 64 arboreal species and 33 families. The recorded diversity was 3.03 nats.ind-1. The six species with greater VIA were: Campsiandra laurifolia Beth., Hevea brasiliensis (Willd. ex A.Juss.) Mull.Arg, Glicoxyson pedicellatum Ducke, Tetragastris altissima (Aubl.) Swart, Vantanea parviflora Lam. And Mabea caudata Pax & K.Hoffm. The spatial pattern of the community has varied because of the considered distance, however it was predominantly aggregated. The spatial patterns detected for the species were: Predominantly random for the Vantanea parviflora; completely aggregated for the Hevea brasiliensis and Glicoxylon pedicellatum species; predominantly aggregated for Camsiandra laurifolia. Tetragastris altissima and Mabea caudata. In Area II, the diametric distribution of Bertholletia excelsa has showed clear tendency to normality, while the spatial pattern was predominantly random. The adaptive sampling methods were inefficient and underestimate the number of individuals per hectare. The simple casual and systematic procedures can be used in Betholletia excelsa forest inventories if there is an increase of sampling intensity for values over 44% the total area.

Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-03-08T18:19:10Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) diego_santos_vieira.pdf: 3296114 bytes, checksum: b738df6d293269169107da9a2300aaa3 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-03-30T15:17:05Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) diego_santos_vieira.pdf: 3296114 bytes, checksum: b738df6d293269169107da9a2300aaa3 (MD5) / Made available in DSpace on 2017-03-30T15:17:05Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) diego_santos_vieira.pdf: 3296114 bytes, checksum: b738df6d293269169107da9a2300aaa3 (MD5) Previous issue date: 2015 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Objetivou-se nesta pesquisa investigar a estrutura e padr?o espacial de uma ?rea de floresta periodicamente inund?vel e suas esp?cies dominantes, de modo a contribuir para defini??o de estrat?gias de manejo e conserva??o (?rea I); analisar a estrutura diam?trica, padr?o espacial e m?todos de amostragem para estimar a densidade de Bertholletia excelsa Bonpl. na Regi?o do Baixo Rio Tapaj?s (?rea II). A ?rea I trata-se de um t?pico fragmento de Floresta Ombr?fila Densa Aluvial utilizado para atender os objetivos do cap?tulo 2, enquanto que a ?rea II representa uma Floresta Ombr?fila Densa de Terra Firme utilizada para atingir os objetivos do cap?tulo 3. Na ?rea I foram instaladas 308 unidades amostrais cont?guas de 10 x 10 m, perfazendo uma ?rea amostral de 3,08 ha. Nessas unidades amostrais, todos os indiv?duos com di?metro a 1,30 m de altura do solo (dap) ? 10 cm foram medidos, identificados e referenciados em coordenadas cartesianas (X,Y). Foram calculados os par?metros fitossociol?gicos de densidade, frequ?ncia, domin?ncia e posi??o sociol?gica, e as esp?cies ordenadas segundo o valor de import?ncia ampliado (VIA). A diversidade e o padr?o espacial foram obtidos atrav?s do ?ndice de Shannon-Weaver e fun??o K de Ripley, respectivamente. Na ?rea II, realizou-se um invent?rio de prospec??o com mapeamento de todas as ?rvores de Bertholletia excelsa Bonpl. com dap ? 20 cm, totalizando 1.000 hectares. Para an?lise da estrutura diam?trica foram utilizadas t?cnicas multivariadas: an?lise de agrupamento e discriminante. Utilizaram-se para an?lise de agrupamento a dist?ncia euclidiana e o m?todo de Ward. O padr?o espacial foi definido por meio do emprego da fun??o univariada K de Ripley. Constatado o padr?o espacial, dividiu-se o mapa em unidades de 50 x 50 m, no qual foram simulados diferentes procedimentos de amostragem (Amostragem Casual Simples, Amostragem Sistem?tica e Amostragem Adaptativa em Cluster) com intensidade amostral de 15% e limite de erro de 10%. As compara??es entre os m?todos foram realizadas por meio do teste F de Graybill e an?lises da precis?o e exatid?o obtidas das 30 simula??es realizadas para cada procedimento. Na ?rea I foram registrados 1.022 indiv?duos, distribu?dos em 64 esp?cies arb?reas e 33 fam?lias. A diversidade registrada foi de 3,03 nats.ind-1. As seis esp?cies de maior VIA foram: Campsiandra laurifolia Beth., Hevea brasiliensis (Willd. ex A.Juss.) Mull.Arg, Glicoxylon pedicellatum Ducke, Tetragastris altissima (Aubl.) Swart, Vantanea parviflora Lam. e Mabea caudata Pax & K.Hoffm. O padr?o espacial da comunidade variou em fun??o da dist?ncia considerada, por?m foi predominantemente agregado. Os padr?es espaciais detectados para as esp?cies foram: predominantemente aleat?rio para a esp?cie Vantanea parviflora; completamente agregado para as esp?cies Hevea brasiliensis e Glicoxylon pedicellatum; predominantemente agregado para Campsiandra laurifolia, Tetragastris altissima e Mabea caudata. Na ?rea II, a distribui??o diam?trica de Bertholletia excelsa apresentou clara tend?ncia ? normalidade, enquanto que o padr?o espacial foi predominantemente aleat?rio. Os m?todos de amostragem adaptativos foram ineficiente e subestimam o n?mero de indiv?duos por hectare. Os procedimentos casual simples e sistem?tico podem ser utilizados para invent?rios florestais de Bertholletia excelsa desde que haja um aumento na intensidade amostral para valores acima de 44% da ?rea total. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2015. / The aim of this research was to investigate the structure and space pattern of a periodically floodable forest area and its prevalent species, in such a way to contribute to the definition of handling and conservation strategies (Area I); analyze the diameter structure, spatial pattern and sampling methods to estimate the Bertholletia excelsa Bonpl density in the Lower Tapaj?s River Region (Area II). Area I is a typical fragment of alluvial Dense Ombrophilous Forest used to accord the objectives of chapter 2, while Area II represent a Solid Ground Dense Ombrophilous Forest used to reach the aims of chapter 3. In Area I 308 contiguous sampling units measuring 10 x10 cm were installed, making a sampling area of 3.08ha. In those sampling units, all the individuals with 1.3m height from the soil (dap) > 10cm were measured, identified and referenced in Cartesian coordinates (X,Y). The phytossociological parameters of density, frequency, dominance and sociological position were calculated, and the species were sorted according to the increased importance rate (VIA). The diversity and the spatial pattern were obtained through the index of Shannon-Weaver and K function of Ripley, respectively. In Area II, an inventory of prospection with the mapping of all Bertholletia excels Bonpl. trees with dap > 20cm was made, totalizing 1,000 hectares. For the analysis of the diametrical structure multi-varied techniques were adopted: grouping analysis and discriminating analysis. To the grouping analysis the Euclidian distance and the Ward method were used. The spatial pattern was defined by employing the univariate Ripley K function. After confirming the spatial pattern, the map was divided into 50 x 50 cm units, in which different sampling procedures were simulated (Simple Casual Sampling, Systematic Sampling and Cluster Adaptive Sampling) with 15% sampling intensity and 10 % error limit. The comparisons between the methods were performed by means of Graybill F test and precision analysis obtained from the 30 simulations performed for each procedure. In Area I 1,022 individuals were recorded, they were distributed into 64 arboreal species and 33 families. The recorded diversity was 3.03 nats.ind-1. The six species with greater VIA were: Campsiandra laurifolia Beth., Hevea brasiliensis (Willd. ex A.Juss.) Mull.Arg, Glicoxyson pedicellatum Ducke, Tetragastris altissima (Aubl.) Swart, Vantanea parviflora Lam. And Mabea caudata Pax & K.Hoffm. The spatial pattern of the community has varied because of the considered distance, however it was predominantly aggregated. The spatial patterns detected for the species were: Predominantly random for the Vantanea parviflora; completely aggregated for the Hevea brasiliensis and Glicoxylon pedicellatum species; predominantly aggregated for Camsiandra laurifolia. Tetragastris altissima and Mabea caudata. In Area II, the diametric distribution of Bertholletia excelsa has showed clear tendency to normality, while the spatial pattern was predominantly random. The adaptive sampling methods were inefficient and underestimate the number of individuals per hectare. The simple casual and systematic procedures can be used in Betholletia excelsa forest inventories if there is an increase of sampling intensity for values over 44% the total area.

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Este trabalho propÃe melhorias em uma tÃcnica de amostragem adaptativa multidimensional para renderizaÃÃo. RenderizaÃÃo à o processo de sÃntese de imagens por meio de algoritmos que simulam a iluminaÃÃo em cenÃrios virtuais. As tÃcnicas mais gerais de renderizaÃÃo fotorrealÃstica â aquelas que procuram obter imagens que se assemelham a fotografias â utilizam mÃtodos de integraÃÃo baseados em Monte Carlo para resolver a equaÃÃo que descreve a distribuiÃÃo de luz na cena (equaÃÃo de renderizaÃÃo). Por ser um mÃtodo probabilÃstico e utilizar amostras geradas randomicamente, Monte Carlo produz ruÃdo na imagem final â resultado da variÃncia das amostras â e portanto, pode necessitar de uma grande quantidade de amostras para que o ruÃdo diminua a nÃveis aceitÃveis. Com o intuito de se obter imagens de melhor qualidade com uma menor quantidade de amostras, foram pospostas tÃcnicas de amostragem adaptativa que visam concentrar o esforÃo de amostragem em regiÃes mais importantes da cena. Neste trabalho, propÃe-se a modificaÃÃo de uma tÃcnica de amostragem adaptativa multidimensional por meio da adiÃÃo de duas etapas: substituiÃÃo de amostras e integraÃÃo auxiliar. Essas etapas visam dar mais robustez à tÃcnica, possibilitando sua utilizaÃÃo em uma maior variedade de situaÃÃes. AlÃm da adiÃÃo de duas etapas, tambÃm propÃe-se uma tÃcnica de reconstruÃÃo mais eficiente na etapa final. / This work proposes improvements in a multidimensional adaptive sampling technique for rendering. Rendering is the process of synthesizing images by algorithms simulating lighting in virtual scenes. The more general techniques of photorealistic rendering â those seeking images that resemble photographs â use integration methods based on Monte Carlo to solve the equation that describes the distribution of light in the scene (rendering equation). Being a probabilistic method which uses randomly generated samples, Monte Carlo produces noise in the final image â result of samplesâ variance â and therefore may require a large amount of samples to reduce the noise to acceptable levels. To obtain images of better quality with a lower number of samples, adaptive sampling techniques were proposed, concentrating sampling effort in the most important regions. In this work, we propose the addition of two steps to a multidimensional adaptive sampling technique: substitution of samples and auxiliary integration. These steps aim to give more strength to the technique, enabling their use in a wider variety of situations.

Proteins and DNA are large, complex molecules that carry out biological functions essential to all life. Their successful operation relies on adopting specific structures, stabilized by intra-molecular interactions between atoms. The spatial and temporal resolution required to study the mechanics of these molecules in full detail can only be obtained using computer simulations of molecular models. In a molecular dynamics simulation, a trajectory of the system is generated, which allows mapping out the states and dynamics of the molecule. However, the time and length scales characteristic of biological events are many orders of magnitude larger than the resolution needed to accurately describe the microscopic processes of the atoms. To overcome this problem, sampling methods have been developed that enhance the occurrence of rare but important events, which improves the statistics of simulation data. This thesis summarizes my work on developing the AWH method, an algorithm that adaptively optimizes sampling toward a target function and simultaneously finds and assigns probabilities to states of the simulated system. I have adapted AWH for use in molecular dynamics simulations. In doing so, I investigated the convergence of the method as a function of its input parameters and improved the robustness of the method. I have also worked on a generally applicable approach for calculating the target function in an automatic and non-arbitrary way. Traditionally, the target is set in an ad hoc way, while now sampling can be improved by 50% or more without extra effort. I have also used AWH to improve sampling in two biologically relevant applications. In one paper, we study the opening of a DNA base pair, which due to the stability of the DNA double helix only very rarely occurs spontaneously. We show that the probability of opening depends on both nearest-neighbor and longer-range sequence effect and furthermore structurally characterize the open states. In the second application the permeability and ammonia selectivity of the membrane protein aquaporin is investigated and we show that these functions are sensitive to specific mutations. / <p>QC 20171117</p>

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The number of technology alternatives has lately grown to satisfy the increasingly demanding goals in modern engineering. These technology alternatives are handled in the design process as either concepts or categorical design inputs. Additionally, designers desire to bring into early design more and more accurate, but also computationally burdensome, simulation tools to obtain better performing initial designs that are more valuable in subsequent design stages. It constrains the computational budget to optimize the design space. These two factors unveil the need of a conceptual design methodology to use more efficiently sophisticated tools for engineering problems with several concept solutions and categorical design choices. Enhanced initial designs and discrete alternative selection are pursued. Advances in computational speed and the development of Bayesian adaptive sampling techniques have enabled the industry to move from the use of look-up tables and simplified models to complex physics-based tools in conceptual design. These techniques focus computational resources on promising design areas. Nevertheless, the vast majority of the work has been done on problems with continuous spaces, whereas concepts and categories are treated independently. However, observations show that engineering objectives experience similar topographical trends across many engineering alternatives. In order to address these challenges, two meta-models are developed. The first one borrows the Hamming distance and function space norms from machine learning and functional analysis, respectively. These distances allow defining categorical metrics that are used to build an unique probabilistic surrogate whose domain includes, not only continuous and integer variables, but also categorical ones. The second meta-model is based on a multi-fidelity approach that enhances a concept prediction with previous concept observations. These methodologies leverage similar trends seen from observations and make a better use of sample points increasing the quality of the output in the discrete alternative selection and initial designs for a given analysis budget. An extension of stochastic mixed-integer optimization techniques to include the categorical dimension is developed by adding appropriate generation, mutation, and crossover operators. The resulted stochastic algorithm is employed to adaptively sample mixed-integer-categorical design spaces. The proposed surrogates are compared against traditional independent methods for a set of canonical problems and a physics-based rotor-craft model on a screened design space. Next, adaptive sampling algorithms on the developed surrogates are applied to the same problems. These tests provide evidence of the merit of the proposed methodologies. Finally, a multi-objective rotor-craft design application is performed in a large domain space. This thesis provides several novel academic contributions. The first contribution is the development of new efficient surrogates for systems with categorical design choices. Secondly, an adaptive sampling algorithm is proposed for systems with mixed-integer-categorical design spaces. Finally, previously sampled concepts can be brought to construct efficient surrogates of novel concepts. With engineering judgment, design community could apply these contributions to discrete alternative selection and initial design assessment when similar topographical trends are observed across different categories and/or concepts. Also, it could be crucial to overcome the current cost of carrying a set of concepts and wider design spaces in the categorical dimension forward into preliminary design.

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Sandia National Laboratories (SNL) currently achieves a bandwidth efficiency (h ) of 0.5 to 1.0 bps/Hz by using traditional modulation schemes, such as, BPSK and QFSK. SNL has an interest in increasing the present bandwidth efficiency by a factor of 4 or higher with the same allocated bandwidth (about 10 MHz). Simulations have shown that 32- QAM trellis-coded modulation (TCM) gives a good bit error rate (BER) performance, and meets the requirements as far as the bandwidth efficiency is concerned. Critical to achieving this is that the receiver be able to achieve timing synchronization. This paper examines a particular timing recovery algorithm for all-digital receivers. Timing synchronization in a digital receiver can be achieved in different ways. One way of achieving this is by interpolating the original sampled sequence to produce another sampled sequence synchronized to the symbol rate or a multiple of the symbol rate. An adaptive sampling conversion algorithm which performs this function was developed by Floyd Gardner in 1993. In the present work, his algorithm was applied to two different modulation schemes, BPSK and 4-ary PAM. The two schemes were simulated in the presence of AWGN and ISI along with Gardner’s algorithm for timing recovery, and a fractionally spaced equalizer (T/2 FSE) for equalization. Simulations show that the algorithm gives good BER performance for BPSK in all the situations, and at different sampling frequencies, but unfortunately poor performance for the 4-ary PAM scheme. This indicates that Gardner’s algorithm for sampling conversion is not suitable for multi-level signaling schemes.