A Passivity-based Nonlinear Admittance Control with Application to Powered Upper-limb Control under Unknown Environmental Interactions

This paper presents an admittance controller based on the passivity theory for a powered upper-limb exoskeleton robot which is governed by the nonlinear equation of motion. Passivity allows us to include a human operator and environmental interaction in the control loop. The robot interacts with the human operator via F/T sensor and interacts with the environment mainly via end-effectors. Although the environmental interaction cannot be detected by any sensors (hence unknown), passivity allows us to have natural interaction. An analysis shows that the behavior of the actual system mimics that of a nominal model as the control gain goes to infinity, which implies that the proposed approach is an admittance controller. However, because the control gain cannot grow infinitely in practice, the performance limitation according to the achievable control gain is also analyzed. The result of this analysis indicates that the performance in the sense of infinite norm increases linearly with the control gain. In the experiments, the proposed properties were verified using 1 degree-of-freedom testbench, and an actual powered upper-limb exoskeleton was used to lift and maneuver the unknown payload.Comment: Accepted in IEEE/ASME Transactions on Mechatronics (T-MECH

System Coverage and Capacity Analysis on Millimeter-Wave Band for 5G Mobile Communication Systems with Massive Antenna Structure

The use of a millimeter-wave band defined as a 30–300 GHz range is significant element for improving performance of 5th generation (5G) mobile communication systems. However, since the millimeter-wave signal has peculiar propagation characteristics especially toward non-line-of-sight regions, the system architecture and antenna structure for 5G mobile communications should be designed to overcome these propagation limitations. For realization of the 5G mobile communications, electronics and telecommunications research institute (ETRI) is developing central network applying various massive antenna structures with beamforming. In this paper, we have introduced the central network and evaluated the system coverage and capacity through C++ language-based simulations with real geospatial information

Changes of phenolic compounds in LebZIP2-overexpressing transgenic plants

484-491The bZIP gene is a transcription factor that plays various roles in relation to plant stress and hormone signaling. This gene is also involved in plant environmental stress and herbicide tolerance. We generated Nicotiana benthamiana transgenic plants with LebZIP2-encoding gene isolated from tomatoes using Agrobacterium-mediated transformation. Transgenic seeds harvested from these T0 transgenic plants were grown and examined for gene transfer and changes in phenolic compounds in the T1 generation. RT-PCR analysis using a primer specific to the LebZIP gene confirmed that the gene was transferred to the T1 generation. We analyzed the increase and decrease tendency for 30 phenolic compounds using the T1 generation-transgenic plants and investigated the mechanism between the specifically increased compound and LebZIP2 gene. Gallic acid, homogentisic acid, protocatechuic acid, myricetin, t-cinnamic acid, and b-resorcyclic acid were identified as the phenolic compounds that increased in T1 transgenic plants overexpressing the LebZIP gene. Among these, homogentisic acid at 246.75-1055.19 µg/g, was increased by 2-5 fold in the T1 transgenic plants compared to the control. Protocatechuic acid was found at 1640.54-2456.00 µg/g and was increased by 2-4 fold in T1 transgenic plants. t-Cinnamic acid was present in a small amount of 23.14 µg/g in the control, whereas it was 102.19-135.47 µg/g in T1 transgenic plants, showing an increase of 4-5 folds. These results indicated that homogentisic acid, protocatechuic acid, and t-cinnamic acid among the 30 phenolic compounds analyzed, were significantly increased in LebZIP2-overexpressing T1 transgenic plants, and support the evidence that the LebZIP2 gene is significantly involved in the increment of three phenolic compounds

Comparison of implant stability after different implant surface treatments in dog bone

OBJECTIVES: The purpose of this investigation was to evaluate the effects of different implant surface treatments on implant stability in dog mandibles. MATERIAL AND METHODS: A total of 30 implants (Dentium Co, Seoul, Korea) were placed in 5 dog mandibles. Bone quality was assessed at each site. Implant stability was evaluated using 2 different methods. An OsstellTM resonance frequency analyzer (RFA) was used to determine the stability at baseline (day 1), and 3, 6 and 10 weeks after surgery. Animals were euthanized 10 weeks after implant installation. Specimens were obtained and submitted to the laboratory processing. Sections were stained with hematoxylin and eosin for histologic and histomorphometric analyses. All implantation sites in dog mandibles demonstrated bone types II and III. RESULTS AND CONCLUSIONS: All implants showed good primary stability at baseline in terms of insertion torque. The results of this study suggest that surface treatment may have significant effects on biological stability 3 weeks after implant placement. Further studies are needed to confirm these initial observations in poor quality bone

Testicular torsion in the inguinal region in an extremely low birth weight infant

Testicular torsion is rare in newborn infants. However, its frequency has increased, most of which are reported in full-term infants. We diagnosed and treated testicular torsion in an extremely low birth weight infant (ELBWI). A 2×2 cm red mass was palpable in the left groin of a 24-week-old, 745 g, male newborn at 23 days of age. Left testicular torsion was diagnosed, and emergent orchiopexy was performed. Careful physical examination is needed in cases suspicious of testicular torsion in ELBWIs with cryptorchidism. Moreover, early diagnosis and emergent exploration are necessary to prevent complications such as the risk of anorchia

Patterns of Using Complementary and Alternative Medicine by Stroke Patients at Two University Hospitals in Korea

This study measured the prevalence of complementary and alternative medicine (CAM) use among Korean stroke patients. Questionnaire-based 20-min interviews were conducted at the hospitals by a trained nurse after an outpatient visit. It included questions on demographic information, clinical information and the utilization of CAM. Of 304 stroke-patient respondents, 164 (54%) had used CAM, of which 66% had started taking CAM products following suggestions from family members and other relatives. Of the 57% of users who felt that CAM was effective, 84% considered that it improved the symptoms of stroke and 16% felt it was effective in achieving psychological relaxation. Of the eight CAM categories used by respondents, 92% used traditional Oriental medical treatments, 36% used plant- and animal-derived over-the-counter health care products, 24% used minerals and vitamins, and 11% used manual therapies. The majority of stroke patients (68%) were trying a new type of CAM, and half of the respondents (45%) relied on the knowledge of their general practitioner about CAMs when deciding whether to use them. Most of the stroke patients in this study used CAM, and a half of them reported beneficial effects. Despite the presence of adverse side effects, they tended to be used without discussion with chief physicians, and hence physicians should be actively involved in the usage of CAM