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Yayın Pros and cons of using building information modeling in the AEC industry(ASCE-AMER Soc Civil Engineers, 2019-08-01) Seyis Kazazoğlu, SenemAlthough a plethora of studies on building information modeling (BIM) have been conducted in the last decade, none of the previous studies collate and/or prioritize the benefits, risks, and challenges of BIM based on the data collected from a comprehensive literature review and subject matter experts (SMEs). In order to allow architecture, engineering, and construction (AEC) professionals and academics see the true potential of BIM in a wider context and help them understand its multiorganizational and multidisciplinary functions, there is an obvious necessity for identifying, classifying, and prioritizing the pros and cons of BIM; however, such a study is still currently absent in the AEC literature. The aim of this study is to identify, classify, and rank the pros and cons of BIM that address the benefits, challenges, and risks of BIM in the transition from computer-aided design (CAD). A literature review was performed and face-to-face semistructured interviews with SMEs on BIM were conducted for identification and classification purposes. A total of 41 types of benefits, 11 types of risks, and 13 types of challenges of BIM were identified via triangulation of literature review and face-to-face semistructured interviews with SMEs. The Delphi method was performed for prioritizing the benefits of BIM in terms of time, cost, and sustainability as well as the risks and challenges of BIM encountered in the transition process from CAD to BIM. The interrater agreement and significance-level statistics were performed to analyze and validate the consensus reached by the Delphi panel experts. This paper contributes to the existing body of knowledge on BIM by providing comprehensive identification and classification of the benefits, challenges, and risks of BIM, and prioritization of the benefits for BIM in terms of time, cost, and sustainability as well as the risks and challenges of BIM. The priority rankings of benefits, risks, and challenges of BIM ensure successful completion of projects and create additional value by allowing professionals to make well-informed decisions that support decreasing time and cost-related waste in the transition process from CAD to BIM.Yayın Coherent array imaging using phased subarrays. Part II: Simulations and experimental results(IEEE-INST Electrical Electronics Engineers Inc, 2005-01) Johnson, Jeremy A.; Oralkan, Ömer; Ergün, Arif Sanlı; Demirci, Utkan; Karaman, Mustafa; Khuri-Yakub, Butrus ThomasThe basic principles and theory of phased subarray (PSA) imaging imaging provides the flexibility of reducing I he number of front-end hardware channels between that of classical synthetic aperture (CSA) imaging-which uses only one element per firing event-and full-phased array (FPA,) imaging-which uses all elements for each firing. The performance of PSA generally ranges between that obtained by CSA and FPA using the same array, and depends on the amount of hardware complexity reduction. For the work described in this paper, we performed FPA, CSA, and PSA imaging of a resolution phantom using both simulated and experimental data from a 3-MHz, 3.2-cm, 128-element capacitive micromachined ultrasound transducer (CMUT) array. The simulated system point responses in the spatial and frequency domains are presented as a means of studying the effects of signal bandwidth, reconstruction filter size, and subsampling rate on the PSA system performance. The PSA and FPA sector-scanned images were reconstructed using the wideband experimental data with 80% fractional bandwidth, with seven 32-element subarrays used for PSA imaging. The measurements on the experimental sector images indicate that, at the transmit focal zone, the PSA method provides a 10% improvement in the 6-dB lateral resolution, and the axial point resolution of PSA imaging is identical to that of FPA imaging. The signal-to-noise ratio (SNR) of PSA image was 58.3 dB, 4.9 dB below that of the FPA image, and the contrast-to-noise ratio (CNR) is reduced by 10%. The simulated and experimental test results presented in this paper validate theoretical expectations and illustrate the flexibility of PSA imaging as a way to exchange SNR and frame rate for simplified front-end hardware.
