The Experts below are selected from a list of 41085 Experts worldwide ranked by ideXlab platform
Kin-lu Wong - One of the best experts on this subject based on the ideXlab platform.
-
Highly-Integrated Dual-Band mmWave Antenna Array for 5G Mobile Phone Application
2020 14th European Conference on Antennas and Propagation (EuCAP), 2020Co-Authors: Wei Chung, Kin-lu WongAbstract:Highly-integrated 28 GHz and 39 GHz array antennas for 5G mobile Phone Applications have been presented. The 28 GHz array consists of dual open-slots antennas as array elements and the 39 GHz array consists of folded loop antennas as array elements. This article demonstrates that 0.25 wavelength slot mode of the open-slots antenna and 1.5 wavelength loop mode of the folded loop antenna are promising candidates for generating directional radiation patterns fulfilling beam-scanning Applications. And by properly designing the 0.25 wavelength slot mode to cover 28 GHz band and the 1.5 wavelength loop mode to cover the 39 GHz band, the proposed 28 GHz and 39 GHz array antennas can be compatible and coexisted at a limited side space of a mobile Phone with keeping independent beam scanning operations for achieving a higher space utilization rate. This will be useful and attractive for future multiband and multimode millimeter wave mobile Phone Applications.
-
small size printed monopole with a printed distributed inductor for pentaband wwan mobile Phone Application
Microwave and Optical Technology Letters, 2009Co-Authors: Chihhua Chang, Kin-lu WongAbstract:In this article, a small-size printed monopole embedded with a printed narrow strip as a distributed inductor for Application in the mobile Phone to achieve GSM850/900/1800/1900/UMTS pentaband wireless wide area network operation is presented. With the printed distributed inductor, the fundamental (lowest) resonant mode of the proposed antenna can be effectively shifted to lower frequencies with a wide operating bandwidth, owing to the contributed inductance of the printed distributed inductor compensating for the increased capacitance resulting from the decreased resonant length of the monopole. In this study, the proposed antenna can be printed on the small no-ground portion of size 14 × 40 mm2 on the main circuit board of the mobile Phone, making it easy to fabricate at low cost and generally showing no thickness above the circuit board; the latter is very attractive for thin-profile mobile Phone Applications. The proposed monopole antenna is studied in detail in this article. The results also show that the antenna is very suitable to be placed at the bottom of the mobile Phone; in this case, the antenna meets the specific absorption rate limit for practical Applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2903–2908, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24775
-
simple folded monopole slot antenna for penta band clamshell mobile Phone Application
IEEE Transactions on Antennas and Propagation, 2009Co-Authors: Fanghsien Chu, Kin-lu WongAbstract:An internal clamshell mobile Phone antenna using a simple dual-band folded monopole slot for covering penta bands of WWAN operation is presented. The folded monopole slot has a length of about 60 mm only and is easily printed on the top portion (10 times 40 mm2) of the main circuit board and suitable to be placed at the hinge of the clamshell mobile Phone. By further placing the connecting strip between the two ground planes to be in the vicinity of the open end of the monopole slot, the two (main and upper) ground planes of the clamshell mobile Phone can also be excited to be efficient radiators (dipole-like chassis or groundplane modes excited through the strong electric field occurred at the slot's open end). By incorporating the resonant modes contributed from both the monopole slot and the two ground planes, two wide bands at about 900 and 1900 MHz are formed, which easily cover GSM850/900/1800/1900/UMTS operation. Owing to the additional resonant modes contributed by the two ground planes, the use of a simple folded monopole slot is sufficient to cover penta-band WWAN operation. This leads to compact size for the proposed clamshell mobile Phone antenna. Details of the proposed antenna, including its SAR results, are presented.
-
small size printed loop antenna for penta band thin profile mobile Phone Application
Microwave and Optical Technology Letters, 2009Co-Authors: Kin-lu Wong, Weiyu ChenAbstract:A planar printed loop antenna with a small area of 15 × 50 mm2 and capable of covering all five operating bands of GSM850/900/1800/1900/UMTS for WWAN (wireless wide area network) operation in the thin-profile mobile Phone is presented. The antenna is very suitable to be directly printed on the system circuit board of the mobile Phone, making it easy to fabricate at low cost and generally showing no thickness above the circuit board; the latter is very attractive for thin-profile mobile Phone Applications. In addition, the proposed loop antenna is very suitable to be printed at the bottom position of the mobile Phone; in this case the antenna meets the SAR (specific absorption rate) limit for practical Applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1512–1517, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24359
-
gsm850 900 1800 1900 umts printed monopole antenna for mobile Phone Application
Microwave and Optical Technology Letters, 2008Co-Authors: Kin-lu Wong, Tingwei KangAbstract:The design of a printed monopole antenna on the system circuit board of the mobile Phone for achieving GSM850/900/1800/1900/UMTS operation with a small area of 10 mm × 60 mm is presented. The antenna is easy to fabricate at low cost and mainly comprises a driven strip, a coupled strip, and a high-pass matching network for providing two wide operating bands at about 900 and 1900 MHz to cover GSM850/900 and GSM1800/1900/UMTS operations, respectively. The wide lower band is controlled by the driven strip excited as a quarter-wavelength mode, which is further tuned to become a dual-resonance excitation by incorporating the high-pass matching network for effective bandwidth enhancement. For the wide upper band, it is formed by a quarter-wavelength mode excited at about 1800 MHz by the coupled strip and the higher-order mode contributed by the driven strip. Furthermore, with the proposed antenna structure, the lower and upper bands can generally be tuned separately, which is an attractive feature and makes it easy to design for practical Applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3192–3198, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23936
Kevin Patrick - One of the best experts on this subject based on the ideXlab platform.
-
Usability and Feasibility of PmEB: A Mobile Phone Application for Monitoring Real Time Caloric Balance
Mobile Networks and Applications, 2007Co-Authors: C C Tsai, G Lee, Gregory J Norman, Timothy Sohn, Fred Raab, William G. Griswold, Kevin PatrickAbstract:Obesity is a major public health challenge with over 65% of US adults either overweight or obese. Estimated annual costs of obesity are $78.5 billion. Self-monitoring is a critical skill for successful weight management. However, self-monitoring is labor-intensive, and compliance is often difficult. In this paper, the authors describe the Patient-Centered Assessment and Counseling Mobile Energy Balance (PmEB) mobile Phone Application that allows users to self-monitor caloric balance in real time. The Application was developed and applied in a four-phase iterative research and development methodology. A usability study and a preliminary feasibility study were conducted. The 1 month feasibility study measured compliance and satisfaction among a sample of 15 participants randomized to one of three groups: (1) a paper diary group, (2) a PmEB group with one daily prompt, and (3) a PmEB group with three daily prompts. PmEB scored highly on usability, compliance, and satisfaction. In addition, mobile Phone group users scored PmEB the same as or better than Paper Group members scored the paper diary in nearly all categories. Thematic analysis of comments revealed very positive reviews of PmEB as well as areas for improvement. PmEB is both usable and feasible for weight management self-monitoring, and the iterative pilot study methodology was effective in improving its usability.
-
usability and feasibility of pmeb a mobile Phone Application for monitoring real time caloric balance
Pervasive Computing Technologies for Healthcare, 2006Co-Authors: C C Tsai, G Lee, Gregory J Norman, Timothy Sohn, W G Grisworld, Kevin PatrickAbstract:Obesity is a major public health challenge with over 65% of U.S. adults either overweight or obese. Estimated annual costs of obesity are around $78.5 billion. Self-monitoring is a critical skill for successful weight management. However, self-monitoring is labor-intensive and compliance is often difficult. In this paper, we describe the Patient-Centered Assessment and Counseling Mobile Energy Balance (PmEB) cell Phone Application that allows users to self-monitor caloric balance in real time. We developed and applied a four-phase iterative research and development methodology. We conducted a usability study and a preliminary feasibility study. The one month feasibility study measured compliance and satisfaction among a sample of 15 participants randomized to one of three groups: 1) a paper diary group, 2) a PmEB group with one daily prompt, and 3) a PmEB group with three daily prompts. PmEB scored highly on usability, compliance, and satisfaction. In addition, cell Phone group users scored PmEB the same as or better than Paper Group members scored the paper diary in nearly all categories. Thematic analysis of comments revealed very positive reviews of PmEB as well as areas for improvement. PmEB is both usable and feasible for self-monitoring in weight management, and our iterative pilot study methodology was effective in improving its usability.
-
pmeb a mobile Phone Application for monitoring caloric balance
Human Factors in Computing Systems, 2006Co-Authors: G Lee, Fred Raab, William G. Griswold, Chris Tsai, Kevin PatrickAbstract:In this paper, we present PmEB, an Application for mobile Phones that allows users to monitor their caloric balance as a part of weight management. PmEB allows users to track their caloric balance by recording food intake and physical activity on their mobile Phones. Daily reminder messages are sent via SMS messages to encourage compliance. Collected data is sent automatically every 24 hours to a central server where it can be analyzed in detail. PmEB was designed as a tool for both users to self-monitor and manage their food consumption and physical activity and primary health care providers to study behavioral patterns in overweight patients. Formative evaluation with seven health-intervention experts and a week-long user study with six clinically overweight, non-expert participants have shown PmEB to have promising potential for improving self-efficacy in dietary and exercise behavior.
Yunwen Chi - One of the best experts on this subject based on the ideXlab platform.
-
internal multiband printed folded slot antenna for mobile Phone Application
Microwave and Optical Technology Letters, 2007Co-Authors: Kin-lu Wong, Yunwen ChiAbstract:A novel printed folded slot antenna suitable for GSM/DCS/PCS/UMTS multiband operation in the mobile Phone is presented. The proposed slot antenna has a planar configuration and is easy to fabricate by printing on the system circuit board of the mobile Phone. The slot antenna has a length of 106 mm and is folded into a compact structure with its two slot ends facing toward each other. This configuration allows the antenna to occupy a small area of 21 × 45 mm2 centered on the top portion of the system ground plane. By feeding the slot antenna using a 50 Ω microstrip line printed along the centerline of the system ground plane, two wide bands (the half- and one-wavelength modes) of the antenna can be generated, with the lower band covering GSM operation and the upper band covering DSC/PCS/UMTS operation. In addition, small excited surface currents in the system ground plane are observed, and the antenna's two operating bands are in general not sensitive to the ground-plane length variations. These features are attractive for practical Applications and different from those of the conventional internal mobile Phone antennas. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1833–1837, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22602
-
internal compact dual band printed loop antenna for mobile Phone Application
IEEE Transactions on Antennas and Propagation, 2007Co-Authors: Yunwen Chi, Kin-lu WongAbstract:A novel dual-band printed loop antenna very promising for Application in mobile Phones as an internal antenna is presented. The antenna comprises an outer loop strip and an inner inverted-L strip connected to and enclosed by the outer loop strip. The antenna occupies a compact area of 15 times 50 mm2 only, yet generating three resonant modes to form two wide bands at about 900 and 1800 MHz for the Global System for Mobile Communication/Digital Communication System operation. Detailed design considerations of the three excited modes are described in the paper. When a shielding metal case is placed close to the antenna, small effects on the antenna's impedance matching are seen, allowing compact integration of the antenna with nearby conducting elements or electronic components. The antenna is also found to result in small excited surface current distributions on the system ground plane of the mobile Phone. This behavior is expected to lead to reduced user's hand effects on the radiation efficiency of the antenna
-
Printed dual-band loop antenna for mobile Phone Application
2007 IEEE Antennas and Propagation Society International Symposium, 2007Co-Authors: Yunwen Chi, Kin-lu WongAbstract:In this paper, we present a novel printed loop antenna for mobile Phone Applications. It occupies an area of 15 times 50 mm only, yet providing two wide operating bands for GSM (Global System for Mobile Communication, 890 ~ 960 MHz) and DCS (Digital Communication System, 1710 ~ 1880 MHz) operation. Detailed design considerations of the antenna and the mechanisms of the mode excitation will be described in this study.
Tim R Cressey - One of the best experts on this subject based on the ideXlab platform.
-
youth friendly services and a mobile Phone Application to promote adherence to pre exposure prophylaxis among adolescent men who have sex with men and transgender women at risk for hiv in thailand a randomized control trial
Journal of the International AIDS Society, 2020Co-Authors: Wipaporn Natalie Songtaweesin, Surinda Kawichai, Nittaya Phanuphak, Tim R Cressey, Prissana Wongharn, Chutima Saisaengjan, Tanat Chinbunchorn, Surang JanyamAbstract:Introduction Strategies are needed to curb the increasing HIV incidence in young men who have sex with men (YMSM) and transgender women (YTGW) worldwide. We assessed the impact of youth-friendly services (YFS) and a mobile Phone Application (app) on adherence to pre-exposure prophylaxis (PrEP) in YMSM and YTGW in Thailand. Methods A randomized control trial was conducted in YMSM and YTGW aged 15 to 19 years. Participants were provided daily oral tenofovir disoproxil fumerate/emtricitabine (TDF/FTC), condoms and randomized to receive either YFS or YFS plus a PrEP app (YFS + APP), whose features included self-assessment of HIV acquisition risk, point rewards and reminders for PrEP and clinic appointments. Clinic visits occurred at zero, one, three and six months and telePhone contact at two, four and five months. HIV testing was performed at every clinic visit. PrEP adherence was evaluated with intracellular tenofovir diphosphate (TFV-DP) concentrations in dried blood spot (DBS) samples at months 3 and 6. The primary endpoint assessed was "PrEP adherence" defined as TFV-DP DBS concentrations ≥700 fmol/punch (equivalent to ≥4 doses of TDF/week). Results Between March 2018 and June 2019, 489 adolescents were screened at three centres in Bangkok. Twenty-seven (6%) adolescents tested positive for HIV and 200 (41%) adolescents participated in the study. Of these, 147 were YMSM (74%) and 53 YTGW (26%). At baseline, median age was 18 years (IQR 17 to 19), 66% reported inconsistent condom use in the past month. Sexually transmitted infection prevalence was 23%. Retention at six months was 73%. In the YFS + APP arm, median app use duration was three months (IQR 1 to 5). PrEP adherence at month 3 was 51% in YFS and 54% in YFS + APP (p-value 0.64) and at month 6 was 44% in YFS and 49% in YFS + APP (p-value 0.54). No HIV seroconversions occurred during 75 person years of follow-up. Conclusions Youth-friendly PrEP services enabled good adherence among half of adolescent PrEP users. However, the mobile Phone Application tested did not provide additional PrEP adherence benefit in this randomized trial. Adolescent risk behaviours are dynamic and require adaptive programmes that focus on "prevention-effective adherence."
G Lee - One of the best experts on this subject based on the ideXlab platform.
-
Usability and Feasibility of PmEB: A Mobile Phone Application for Monitoring Real Time Caloric Balance
Mobile Networks and Applications, 2007Co-Authors: C C Tsai, G Lee, Gregory J Norman, Timothy Sohn, Fred Raab, William G. Griswold, Kevin PatrickAbstract:Obesity is a major public health challenge with over 65% of US adults either overweight or obese. Estimated annual costs of obesity are $78.5 billion. Self-monitoring is a critical skill for successful weight management. However, self-monitoring is labor-intensive, and compliance is often difficult. In this paper, the authors describe the Patient-Centered Assessment and Counseling Mobile Energy Balance (PmEB) mobile Phone Application that allows users to self-monitor caloric balance in real time. The Application was developed and applied in a four-phase iterative research and development methodology. A usability study and a preliminary feasibility study were conducted. The 1 month feasibility study measured compliance and satisfaction among a sample of 15 participants randomized to one of three groups: (1) a paper diary group, (2) a PmEB group with one daily prompt, and (3) a PmEB group with three daily prompts. PmEB scored highly on usability, compliance, and satisfaction. In addition, mobile Phone group users scored PmEB the same as or better than Paper Group members scored the paper diary in nearly all categories. Thematic analysis of comments revealed very positive reviews of PmEB as well as areas for improvement. PmEB is both usable and feasible for weight management self-monitoring, and the iterative pilot study methodology was effective in improving its usability.
-
usability and feasibility of pmeb a mobile Phone Application for monitoring real time caloric balance
Pervasive Computing Technologies for Healthcare, 2006Co-Authors: C C Tsai, G Lee, Gregory J Norman, Timothy Sohn, W G Grisworld, Kevin PatrickAbstract:Obesity is a major public health challenge with over 65% of U.S. adults either overweight or obese. Estimated annual costs of obesity are around $78.5 billion. Self-monitoring is a critical skill for successful weight management. However, self-monitoring is labor-intensive and compliance is often difficult. In this paper, we describe the Patient-Centered Assessment and Counseling Mobile Energy Balance (PmEB) cell Phone Application that allows users to self-monitor caloric balance in real time. We developed and applied a four-phase iterative research and development methodology. We conducted a usability study and a preliminary feasibility study. The one month feasibility study measured compliance and satisfaction among a sample of 15 participants randomized to one of three groups: 1) a paper diary group, 2) a PmEB group with one daily prompt, and 3) a PmEB group with three daily prompts. PmEB scored highly on usability, compliance, and satisfaction. In addition, cell Phone group users scored PmEB the same as or better than Paper Group members scored the paper diary in nearly all categories. Thematic analysis of comments revealed very positive reviews of PmEB as well as areas for improvement. PmEB is both usable and feasible for self-monitoring in weight management, and our iterative pilot study methodology was effective in improving its usability.
-
pmeb a mobile Phone Application for monitoring caloric balance
Human Factors in Computing Systems, 2006Co-Authors: G Lee, Fred Raab, William G. Griswold, Chris Tsai, Kevin PatrickAbstract:In this paper, we present PmEB, an Application for mobile Phones that allows users to monitor their caloric balance as a part of weight management. PmEB allows users to track their caloric balance by recording food intake and physical activity on their mobile Phones. Daily reminder messages are sent via SMS messages to encourage compliance. Collected data is sent automatically every 24 hours to a central server where it can be analyzed in detail. PmEB was designed as a tool for both users to self-monitor and manage their food consumption and physical activity and primary health care providers to study behavioral patterns in overweight patients. Formative evaluation with seven health-intervention experts and a week-long user study with six clinically overweight, non-expert participants have shown PmEB to have promising potential for improving self-efficacy in dietary and exercise behavior.