A plug-and-play ripple mitigation approach for DC-links in hybrid systems

© 2016 IEEE.In this paper, a plug-and-play ripple mitigation technique is proposed. It requires only the sensing of the DC-link voltage and can operate fully independently to remove the low-frequency voltage ripple. The proposed technique is nonintrusive to the existing hardware and enables hot-swap operation without disrupting the normal functionality of the existing power system. It is user-friendly, modular and suitable for plug-and-play operation. The experimental results demonstrate the effectiveness of the ripple-mitigation capability of the proposed device. The DC-link voltage ripple in a 110 W miniature hybrid system comprising an AC/DC converter and two resistive loads is shown to be significantly reduced from 61 V to only 3.3 V. Moreover, it is shown that with the proposed device, the system reliability has been improved by alleviating the components' thermal stresses

Current status of robot-assisted surgery

The introduction of robot-assisted surgery, and specifically the da Vinci Surgical System, is one of the biggest breakthroughs in surgery since the introduction of anaesthesia, and represents the most significant advancement in minimally invasive surgery of this decade. One of the first surgical uses of the robot was in orthopaedics, neurosurgery, and cardiac surgery. However, it was the use in urology, and particularly in prostate surgery, that led to its widespread popularity. Robotic surgery, is also widely used in other surgical specialties including general surgery, gynaecology, and head and neck surgery. In this article, we reviewed the current applications of robot-assisted surgery in different surgical specialties with an emphasis on urology. Clinical results as compared with traditional open and/or laparoscopic surgery and a glimpse into the future development of robotics were also discussed. A short introduction of the emerging areas of robotic surgery were also briefly reviewed. Despite the increasing popularity of robotic surgery, except in robot-assisted radical prostatectomy, there is no unequivocal evidence to show its superiority over traditional laparoscopic surgery in other surgical procedures. Further trials are eagerly awaited to ascertain the long-term results and potential benefits of robotic surgery.published_or_final_versio

Dogs Have Masters

The vignette "Dogs Have Masters" deals with the role of transition and the power of transformation as it applies to the roles of loss, offering, sacrifice and protection. Ceramic traditions of containment, corporeal metaphor and the allegorical reference of earth are examined through an awakening of subconscious and conscious meaning and associations. Commercial porcelains and unfired terra cotta become engaged in a visual dialogue based upon the idiom of binary opposites that create universal balances. Ceramics is shown here as opposition ends of the spectrum leading to the same sobering and perhaps unexpected conclusion: even in death, clay is man's best friend. The imagery was chosen from a wide range of influences: Japanese gardens of old Kyoto; Egyptian mythology with its systematic blueprints for an eternal afterlife; the phrasing of the Spanish poet Juan Ramon Jimenez; the gay nightclubs of my youth and the coded messages of American jazz music

PCNL trajectory: a novel concept to predict success in supine PCNL

香港泌尿外科學會Oral (Free Paper) Session IV - Andrology, Men’s Health and Stone Disease: OP.4-5OBJECTIVE: Supine PCNL confers certain advantages over its prone counterpart but access parameters change with supine positioning. Supine position limits maneuverability of instruments, limiting access to upper and mid-pole stones. We aim to determine predictive factors for success of supine PCNL through road-mapping of ...published_or_final_versionThe 17th Annual Scientific Meeting of the Hong Kong Urological Association, Hong Kong, 6 November 2011. In Program Book, 2011, p. 5

PCNL trajectory to predict success in supine PCNL: a novel concept

This journal suppl. contatin program & abstracts of the 29th World Congress of Endourology & SWL WCE, 2011Session - MP23: PNL 2: abstract no. MP23-13INTRODUCTION: Supine PCNL confers certain advantages over prone. Access parameters change with positioning. Supine position limits maneuverability of instruments, limiting access to upper & mid-pole stones. We aim to determine predictive factors for success of supine PCNL through road-mapping of PCNL trajectory. MATERIAL & METHOD: Consecutive patients undergoing PCNL from July-Dec2010 were recruited. Choice of position was made by surgeon. Tracts were performed under USG & fluoroscopy. Distances and angles were measured intra-operatively with rigid and flexible nephroscope, and correlated with pre-operative imaging. RESULTS 19 patients underwent PCNL(13supine, 6prone) Stone load was comparable in both groups. Overall stone clearance after single PCNL was 74%. Regardless of abdominal thickness and approach, all lower pole and renal pelvic stones were reached with mean excursion of 140 mm in supine & 105 mm in prone position. Mean entry angle was 59 for supine, and 35 for prone. In supine PCNL, the upper pole was reached in 4 of 11 tracts, with mean-excursion of 172mm& entry angle of 33. Similarly, 2 of 11 supine PCNL reached middle pole. Conversely, all prone PCNL tracts reached upper & middle pole with decreased excursion & angle. CONCLUSION: PCNL in prone position can reach renal pelvis and 3 poles via lower pole puncture. PCNL trajectory may be a tool to predict success in supine PCNL by estimating chance of reaching mid & upper pole. Skin to upper pole distance larger than 185mm and entry angle more than 48 degrees decrease chance of upper pole access.published_or_final_versionThe 29th World Congress of Endourology & SWL WCE, Kyoto, Japan, 30 November–3 December 2011. In Journal of Endourology, v. 25 suppl 1, p. A145, abstract no. MP23-1

Scalability of Quasi-hysteretic FSM-based Digitally Controlled Single-inductor Dual-string Buck LED Driver To Multiple Strings

There has been growing interest in Single-Inductor Multiple-Output (SIMO) DC-DC converters due to its reduced cost and smaller form factor in comparison with using multiple single-output converters. An application for such a SIMO-based switching converter is to drive multiple LED strings in a multi-channel LED display. This paper proposes a quasi-hysteretic FSM-based digitally controlled Single-Inductor Dual-Output (SIDO) buck switching LED Driver operating in Discontinuous Conduction Mode (DCM) and extends it to drive multiple outputs. Based on the time-multiplexing control scheme in DCM, a theoretical upper limit of the total number of outputs in a SIMO buck switching LED driver for various backlight LED current values can be derived analytically. The advantages of the proposed SIMO LED driver include reducing the controller design complexity by eliminating loop compensation, driving more LED strings without limited by the maximum LED current rating, performing digital dimming with no additional switches required, and optimization of local bus voltage to compensate for variability of LED forward voltage (VF) in each individual LED string with smaller power loss. Loosely-binned LEDs with larger VF variation can therefore be used for reduced LED costs.postprin

Adaptive High-Bandwidth Digitally Controlled Buck Converter with Improved Line and Load Transient Response

Digitally controlled switching converter suffers from bandwidth limitation because of the additional phase delay in the digital feedback control loop. In order to overcome the bandwidth limitation without using a high sampling rate, this paper presents an adaptive third-order digital controller for regulating a voltage-mode buck converter with a modest 2x oversampling ratio. The phase lag due to the ADC conversion time delay is virtually compensated by providing an early estimation of the error voltage for the next sampling time instant, enabling a higher unity-gain bandwidth without compromising stability. An additional pair of low-frequency pole and zero in the third-order controller increases the low-frequency gain, resulting in faster settling time and smaller output voltage deviation during line transient. Both simulation and experimental results demonstrate that the proposed adaptive third-order controller reduces the settling time by 50% in response to a 1 V line transient and 30% in response to a 600 mA load transient, compared to the baseline static second-order controller. The fastest settling time is measured to be around 11.70 s, surpassing the transient performance of conventional digital controllers and approaching that of the state-of-the-art analog-based controllers.postprin