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ABSTRACT: Conventionally a phase-shift detection method (PSDM) and a frequency-shift detection method (FSDM) have been used in loop detectors. The PSDM has a fast response time and is very effective in detecting vehicles traveling at normal speeds. However, it is well known that the detection results are erroneous for vehicles traveling at low speeds in heavy traffic conditions. On the other hand, the FSDM greatly improves the detector performance for heavy traffic conditions. However, this method is not effective in fast and normal traffic conditions. Thus, in order to collect accurate traffic data for all traffic conditions, this paper proposes combining two methods using the digital OR logic. In the developed circuit, a phase-locked loop (PLL) circuit is used for measuring the phase change. This paper also develops a new loop detector instrumentation method using the so-called M circuit for detecting frequency change. The developed method has been tested for various traffic conditions. Experimental results show that the new combined M and PLL detection method greatly improves the accuracy in all traffic conditions, reducing the error rate in measuring traffic flow by more than 83%, when compared to the PSDM.
Vehicle System Dynamics 08/2010; May 2002(Vol. 37):377-394. · 0.72 Impact Factor
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ABSTRACT: Efficient delivery systems are required to exploit the enormous potential of RNA interference. We introduced an arginine peptide-based small-interference RNA (siRNA) delivery system for in vitro and in vivo RNA interference. Arginine peptides formed stable complexes with siRNA and transduced siRNA into COS-7 cells in vitro, resulting in efficient gene silencing. The intracellular path of the peptide/siRNA complex was investigated in live cells using fluorescent labeling and confocal microscopy. At 24h after transfection, most of the siRNA signals were observed in the perinuclear region, indicating that siRNA was targeted to the perinuclear region for interactions with RNA-induced silencing complex (RISC). Effective in vivo RNA interference was achieved in a mouse model bearing a subcutaneous tumor. Intratumoral administration of HER-2-specific siRNA/peptide complexes resulted in a marked reduction of tumor growth. Body weight monitoring during treatment showed that our delivery system was nontoxic. Our approach offers the potential for siRNA delivery in various in vitro and in vivo applications.
Journal of Controlled Release 05/2010; 143(3):335-43. · 5.73 Impact Factor
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ABSTRACT: Wide-ranging costs of laparoscopic surgery (LAP) are associated with variations in the experience levels of surgeons. There is no available report on the changes of economic outcomes relative to the LAP learning curve in the treatment of colorectal cancer. In the present study, we have compared changes in economic outcomes according to the LAP learning curve with the economic outcomes of open surgery (OS) for rectosigmoid cancer.
A total of 197 patients with rectosigmoid cancer were included in this analysis; 116 received LAP and 81 received OS. Scatter of operative times demonstrated an early learning period of 37 cases in LAP. The following outcomes were compared between LAP and OS during the early learning period and experienced periods; operating room (OR) costs, OR-related hospital profit, total hospital charge, and patient payment. During the median interval of two periods according to the laparoscopic surgery learning curve, there was an inflation rate of about 10% on the medical charges such as operation, radiology, laboratory, and admission fee.
Operating room costs were significantly higher after LAP during the two periods, but the median difference between LAP and OS decreased during the experienced period ($3,055 to $1,850). With increasing operative experience in LAP, the OR-related hospital deficit improved (-$1,072 to-$840). Total hospital charges were significantly higher for LAP than for OS in the early learning period (p < 0.05), but they were similar in the experienced period ($7,983/patient versus $7,045/patient, p > 0.05). During the experienced period, patients paid a lower surcharge for LAP ($1,885-$1,118).
Total hospital charges for laparoscopic surgery were substantially higher than those of open surgery during the early learning period, but become similar during the experienced period. The shortening of the learning period is a critical factor for achieving cost-effective laparoscopic surgery.
World Journal of Surgery 10/2007; 31(9):1827-34. · 2.36 Impact Factor
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ABSTRACT: To compare the economic outcomes of laparoscopic surgery (LAP) with those of open surgery (OS) for colorectal cancer.
We compared operating room (OR) costs, OR hospital-profits, total hospital charges, and payments made for 67 consecutive patients who underwent either OS (n = 41) or LAP (n = 26) for colorectal cancer.
The operating time was longer in the LAP group (P < 0.001), but the hospital stay was shorter (P < 0.001). OR costs were higher in the LAP group, which was primarily attributed to the higher costs of consumables (LAP 1441, OS 575 dollars; P < 0.001) and the longer operating time (LAP 215 min, OS 155 min; P < 0.001). Total hospital charges were also higher after LAP (LAP 5017 dollars, OS 4093 dollars; P < 0.001). Patients paid more after LAP (P < 0.001), but there was no significant difference between the two groups in National Health Insurance Corporation payments.
Laparoscopic surgery is less cost-effective than OS for colorectal cancer. The higher costs of consumables and the longer operating time associated with LAP must be addressed to make LAP more cost-effective.
Surgery Today 02/2007; 37(2):127-32. · 1.22 Impact Factor
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ABSTRACT: The design of high power push-pull amplifier and unique balun structure are presented. The balun consists of a dielectric resonator and slot line. In comparison with previous balun made up with cavity fixture by G.J. Laughlin (1976), the proposed one can be easily implemented due to its simple structure. The experimental result shows that push-pull amplifier has a gain of 13.7dB at the 2.1GHz W-CDMA band. With two carrier W-CDMA signal, the push-pull amplifier achieves an efficiency of 18.8% at the 41.5dBm average output power and ACLR test results of 36.7dBc at the 5MHz offset and 43.6dBc at the 10MHz offset.
Microwave Symposium Digest, 2004 IEEE MTT-S International; 07/2004
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ABSTRACT: Push-pull structure with balun transformer is presented as load modulation technique which improves the overall efficiency of power amplifier. Under the assumption that output impedance of turned-off amplifier is high, conventional Doherty amplifier is composed of impedance inverter and additional peaking amplifier. In many case, however, output impedance of 'off' amplifier is very low due to matching network or parasitic output capacitance. This paper introduces novel load modulation technique with push-pull structure which uses low impedance characteristic of off amplifier. Experimental results show that efficiency enhancement and good linearity of the proposed structure. To the authors' knowledge this is the first experimental results with a push-pull structure Doherty amplifier.
Microwave Symposium Digest, 2004 IEEE MTT-S International; 07/2004
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ABSTRACT: Concerns vehicle detectors, which collect passing vehicle
information and traffic condition in real time. This paper develops an
ultrasonic vehicle detector (UVD) system that can be implemented in a
side-fire configuration. Conventionally, UVD systems are installed in
overhead configurations. If these sensors can be mounted from the side
of a road, the installation cost can be reduced. In addition, the
aesthetic integrity of roadways will not be affected very much. However,
this side-fire configuration has not been used, because of the fact that
vehicles generally do not have sufficiently large oblique-angled
surfaces to reflect the emitted ultrasonic wave back to the sensor for
detection. This paper reports on the feasibility of a side-fire UVD
system. A new low-cost instrumentation and control system for side-fire
implementation was developed, and comprehensive experiments were
performed at highway and downtown test sites. Experimental conditions
included various traffic conditions as well as various weather
conditions, including daylight, dusk, night, heavy rain, and heavy snow.
Traffic data were generated for every five minutes. For the highway
location, the vehicle counting error was less than 1%. For the downtown
location, the error was approximately 3% during normal weather
conditions and approximately 5% during a snow storm. The larger error in
downtown is mainly attributed to vehicles changing lane. We believe that
these side-fire implementation results are adequate for implementing
advanced traveler information systems (ATIS)
IEEE Transactions on Intelligent Transportation Systems 10/2001; · 3.45 Impact Factor
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IEEE Transactions on Intelligent Transportation Systems. 01/2001; 2:127-134.
