PENDUGAAN DATA HILANG PADA RANCANGAN ACAK KELOMPOK LENGKAP DENGAN METODE YATES DAN ALGORITMA EXPECTATION MAXIMIZATION

Dalam sebuah percobaan, seringkali percobaan tidak selamanya berjalan sesuai dengan yang diharapkan. Jika data yang diperoleh dari suatu penelitian hanya sebagian teramati, maka masalah umum dalam percobaan telah terjadi yang dikenal sebagai data hilang. Hal tersebut dapat disebabkan oleh berbagai hal, misalnya perlakuan yang tidak tepat, kerusakan pada obyek percobaan dan data yang tidak logis. Nilai-nilai yang hilang tersebut harus diduga dan diganti sebelum melakukan analisis lebih lanjut. Metode pendugaan data hilang dalam penelitian ini adalah metode Yates dan Algoritma EM. Konsep dasar dalam metode Yates adalah meminimumkan jumlah kuadrat galat, sedangkan konsep dasar Algoritma EM adalah memaksimumkan fungsi likelihood. Pengaplikasian penelitian ini pada Rancangan Acak Kelompok Lengkap (RAKL) dengan besaran perlakuan yang berbeda (3 perlakuan sampai dengan 7 perlakuan) pada 3 kelompok. Pendugaan data hilang dengan metode Algoritma EM lebih baik digunakan dari pada metode Yates jika posisi data hilang secara acak dan dalam satu perlakuan, berbeda halnya jika data hilang dalam satu kelompok lebih baik menggunakan metode Yates dibandingkan metode Algoritma EM. Pendugaan data hilang dengan metode Yates dan algoritma EM menghasilkan nilai dugaan yang sama jika ada 1 data hilang, sehingga sama-sama baik digunakan. Kata Kunci : Rancangan acak kelompok lengkap, data hilang, metode Yates, metode Algoritma E

Damage avoidance design steel beam-column moment connection using high-force-to-volume dissipators

Existing welded steel moment frames are designed to tolerate substantial yielding and plastic rotation under earthquake loads. This sacrificial design approach can lead to permanent, and often irreparable damage when interstory drifts exceed 2%. The experimental seismic performance of a 50% full-scale damage avoidance designed structural steel beam-column connection is presented. The beam-column joint region consists of a top flange-hung beam connected to the column by an angle bracket. High-force-to-volume (HF2V) devices are attached from the column to the beam to provide joint rigidity and energy dissipation as the joint opens and closes. The HF2V devices are connected either below the beam flange or concealed above the beam's lower flange. Reversed cyclic lateral load tests are conducted with drift amplitudes up to 4%. No damage is observed in the principal beam and column structural elements. The need for stiff device connections to achieve optimal device performance is demonstrated, and potential design solutions presented. Stable hysteresis and repeatable energy dissipation for a large number of cycles up to the 4% drift level is observed. It is concluded that superior and repeatable energy dissipation without damage can be achieved for every dynamic motion cycle, in contrast to conventional sacrificially designed welded moment frame connections

Improved seismic hazard model with application to probabilistic seismic demand analysis

An improved seismic hazard model for use in performance-based earthquake engineering is presented. The model is an improved approximation from the so-called 'power law' model, which is linear in log-log space. The mathematics of the model and uncertainty incorporation is briefly discussed. Various means of fitting the approximation to hazard data derived from probabilistic seismic hazard analysis are discussed, including the limitations of the model. Based on these 'exact' hazard data for major centres in New Zealand, the parameters for the proposed model are calibrated. To illustrate the significance of the proposed model, a performance-based assessment is conducted on a typical bridge, via probabilistic seismic demand analysis. The new hazard model is compared to the current power law relationship to illustrate its effects on the risk assessment. The propagation of epistemic uncertainty in the seismic hazard is also considered. To allow further use of the model in conceptual calculations, a semi-analytical method is proposed to calculate the demand hazard in closed form. For the case study shown, the resulting semi-analytical closed form solution is shown to be significantly more accurate than the analytical closed-form solution using the power law hazard model, capturing the 'exact' numerical integration solution to within 7% accuracy over the entire range of exceedance rat

Influence of Vertical Ground Motions on the Seismic Fragility Modeling of a Bridge-Soil-Foundation System

This paper explores the effects of vertical ground motions (VGMs) on the component fragility of a coupled bridged-soil-foundation (CBSF) system with liquefaction potential, and highlights the unique considerations on the demand and capacity model required for fragility analysis under VGMs. Optimal intensity measures (IMs) that account for VGMs are identified. Moreover, fragility curves that consider capacity change with fluctuating axial force are derived. Results show that the presence of VGMs has a minor effect on the failure probabilities of piles and expansion bearings, while it has a great influence on fixed bearings. Whether VGMs have an impact on column fragilities depends on the design axial load ratio. Finally, more accurate fragility surfaces are derived, which are compared with results of conventional fragility curves. This study highlights the important role that VGMs play in the selection of optimal IMs, and the capacity and fragility representation of certain components of CBSF systems

INNODIA Master Protocol for the evaluation of investigational medicinal products in children, adolescents and adults with newly diagnosed type 1 diabetes

Background The INNODIA consortium has established a pan-European infrastructure using validated centres to prospectively evaluate clinical data from individuals with newly diagnosed type 1 diabetes combined with centralised collection of clinical samples to determine rates of decline in beta-cell function and identify novel biomarkers, which could be used for future stratification of phase 2 clinical trials. Methods In this context, we have developed a Master Protocol, based on the "backbone" of the INNODIA natural history study, which we believe could improve the delivery of phase 2 studies exploring the use of single or combinations of Investigational Medicinal Products (IMPs), designed to prevent or reverse declines in beta-cell function in individuals with newly diagnosed type 1 diabetes. Although many IMPs have demonstrated potential efficacy in phase 2 studies, few subsequent phase 3 studies have confirmed these benefits. Currently, phase 2 drug development for this indication is limited by poor evaluation of drug dosage and lack of mechanistic data to understand variable responses to the IMPs. Identification of biomarkers which might permit more robust stratification of participants at baseline has been slow. Discussion The Master Protocol provides (1) standardised assessment of efficacy and safety, (2) comparable collection of mechanistic data, (3) the opportunity to include adaptive designs and the use of shared control groups in the evaluation of combination therapies, and (4) benefits of greater understanding of endpoint variation to ensure more robust sample size calculations and future baseline stratification using existing and novel biomarkers.Peer reviewe

Reproductive innovations and pulsed rise in plant complexity

Morphological complexity is a notable feature of multicellular life, although whether it evolves gradually or in early bursts is unclear. Vascular plant reproductive structures, such as flowers, are familiar examples of complex morphology. In this study, we use a simple approach based on the number of part types to analyze changes in complexity over time. We find that reproductive complexity increased in two pulses separated by ~250 million years of stasis, including an initial rise in the Devonian with the radiation of vascular plants and a pronounced increase in the Late Cretaceous that reflects flowering plant diversification. These pulses are associated with innovations that increased functional diversity, suggesting that shifts in complexity are linked to changes in function regardless of whether they occur early or late in the history of vascular plants

Professionalism and person-centredness: developing a practice based approach to leadership within NHS maternity services in the UK

This paper, based on data taken from in-depth interviews with senior midwives and obstetricians and conducted as part of a critical ethnographic study, argues for a greater appreciation of person-centred, value-led midwifery practice. The paper begins with a discussion of the way midwifery practice is shaped by encoded and embodied knowledge. The paper subsequently focuses on an emergent practice based leadership using an adapted Aristotelian conceptual framework derived from MacIntyre (2007). Professional dissonance is highlighted as a difficulty experienced by repositioned managers who are also expected to be leaders in their field. Using data gathered from in-depth interviews it is contended that establishing person-centred care might be better achieved through the development of practice based leadership (rather than solely by adherence to organisational requirements). This type of leadership could potentially nurture a professional environment that promotes qualities, such as agency, commitment and high levels of competence among midwives. Such leadership is central to UK government priorities and is applicable to a global practice development agenda

A case study evaluation of implementation of a care pathway to support normal birth in one English birth centre: anticipated benefits and unintended consequences

Background: The policy drive for the UK National Health Service (NHS) has focused on the need for high quality services informed by evidence of best practice. The introduction of care pathways and protocols to standardise care and support implementation of evidence into practice has taken place across the NHS with limited evaluation of their impact. A multi-site case study evaluation was undertaken to assess the impact of use of care pathways and protocols on clinicians, service users and service delivery. One of the five sites was a midwifery-led Birth Centre, where an adapted version of the All Wales Clinical Pathway for Normal Birth had been implemented. Methods: The overarching framework was realistic evaluation. A case study design enabled the capture of data on use of the pathway in the clinical setting, use of multiple methods of data collection and opportunity to study and understand the experiences of clinicians and service users whose care was informed by the pathway. Women attending the Birth Centre were recruited at their 36 week antenatal visit. Episodes of care during labour were observed, following which the woman and the midwife who cared for her were interviewed about use of the pathway. Interviews were also held with other key stakeholders from the study site. Qualitative data were content analysed. Results: Observations were undertaken of four women during labour. Eighteen interviews were conducted with clinicians and women, including the women whose care was observed and the midwives who cared for them, senior midwifery managers and obstetricians. The implementation of the pathway resulted in a number of anticipated benefits, including increased midwifery confidence in skills to support normal birth and promotion of team working. There were also unintended consequences, including concerns about a lack of documentation of labour care and negative impact on working relationships with obstetric and other midwifery colleagues. Women were unaware their care was informed by a care pathway. Conclusion: Care pathways are complex interventions which generate a number of consequences for practice. Those considering introduction of pathways need to ensure all relevant stakeholders are engaged with this and develop robust evaluation strategies to accompany implementation