• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.171-179
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• 2004

The purpose of this study is to generate cycling motion for FES (functional electrical stimulation) using knee muscles only. We investigated the possibility by simulation. The musculoskeletal model used in this simulation was simplified as 5-rigid links and 2 muscles (knee extensor and flexor). For the improvement of the present feedforward control in FES, we included feedback path in the control system. The control system was developed based on the biological neuronal system and was represented by three sub-systems. The first is a higher neuronal system that generates the motion command for each joint. The second is the lower neuronal system that divides the motion command to each muscle. And the third is a sensory feedback system corresponding to the somatic sensory system. Control system parameters were adjusted by a genetic algorithm (GA) based on the natural selection theory. GA searched the better parameters in terms of the cost function where the energy consumption, muscle force smoothness, and the cycling speed of each parameter set (individual) are evaluated. As a result, cycling was implemented using knee muscles only. The proposed control system based on the nervous system model worked well even with disturbances.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.10
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• pp.933-938
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• 2010

In this paper, we propose the organization of a sensor system and user's intent detection algorithm for walking assist rehabilitation robots. The main purpose of walking assist rehabilitation robots is assisting SCI patients to walk in normal environment. To use walking assist rehabilitation robot in normal environment, it is needed to consider various factors about user's safety and detection of user's intent and so on. For these purposes, we have analyzed the use case of rehabilitation robots and organized the system of sensors for walking assist rehabilitation robots and finally, we have developed the algorithm which is used to detect user's intent for those. We applied our proposal method in the rehabilitation robot, ROBIN, and verified their effectiveness by normal, not patient.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.924-944
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• 2017

Telecare Medical Information System (TMIS) helps the patients to gain the health monitoring information at home and access medical services over the mobile Internet. In 2015, Das et al proposed a secure and robust user AKA scheme for hierarchical multi-medical server environment in TMIS, referred to as DAKA protocol, and claimed that their protocol is against all possible attacks. In this paper, we first analyze and show DAKA protocol is vulnerable to internal attacks, impersonation attacks and stolen smart card attack. Furthermore, DAKA protocol also cannot provide confidentiality. We then propose a lightweight pseudonym AKA protocol for multi-medical server architecture in TMIS (short for PAKA). Our PAKA protocol not only keeps good security features declared by DAKA protocol, but also truly provides patient's anonymity by using pseudonym to protect sensitive information from illegal interception. Besides, our PAKA protocol can realize authentication and key agreement with energy-saving, extremely low computation cost, communication cost and fewer storage resources in smart card, medical servers and physical servers. What's more, the PAKA protocol is proved secure against known possible attacks by using Burrows-Abadi-Needham (BAN) logic. As a result, these features make PAKA protocol is very suitable for computation-limited mobile device.

• The Korean Journal of Zoology
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• v.37 no.4
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• pp.533-544
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• 1994

정신분열 살인환자로 격리 치료를 받고 있는 집단을 대상으로 이들을 치료하고자 복용시키는 Haloperidol, Perphenazine, Lithium carbonate 등과 같은 항정신질환 치료제가 자매염색분체 교환(Sister Chromatid Exchange SCE)에 미치는 영향을 조사하였다. 항정신질환 치료제를 계속적으로 복용하고 있는 환자 100명(남자: 76명, 여자: 24명)과 치료제를 전혀 복용하지 않은 남자 환자 10명을 대조군으로 하여 SCE의 빈도를 분석한 결과 항정신질환 치료제를 복용한 환자군에서의 SCE 평균빈도는 세포당 12.24$\pm$0.20으로 항정신질환 치료제를 복용하지 않은 대조군에서의 평균빈도인 세포당 8.77$\pm$0.20보다 높아 유의한 차이를 볼 수 있었다 그러나 항정신질환 치료제를 복용하지 않은 대조군에서의 평균빈도는 이미 보고된 바 있는 정상인 한국인 집단에서의 평균빈도인 세포당 8.78$\pm$0.24(Park et al. , 1992)와 별 차이가 없었다 한편 항정신질환 치료제를 장기간 복용하는데 따른 SCI 빈도의 차이가 있는지의 여부를 보기 위하여 1년 미만에서 6년 정도까지의 치료제 복용기간에 따른 SCE의 평균빈도를 비교 분석한 바 복용기간에 따른 SCE 평균빈도의 유의한 차이는 볼 수 없었다. 정신분열환자들이 복용하고 있는 항정신질환 치료제가 SCE에 영향을 줄 수 있다는 결과를 얼었다.

• Physical Therapy Korea
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• v.3 no.3
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• pp.32-43
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• 1996

The purpose of this case study was to introduce functional electrical stimulation(FES) for paraplegic patients. FES provides the ability to rise from sitting to standing, maintenance of a standing position, and the ability to walk with a reciprocal gait. Six channels of electrical stimulation are sufficient for synthesis of a simple reciprocal gait pattern in these patients. During the double-stance phase, knee extensor muscles of both knees are stimulated, providing sufficient support for the body. Only one knee extensor muscle group is excited during the single-stance phase. The swing phase of the contralateral lower extremity is accomplished by eliciting the synergic flexor muscle response through electrical stimulation of afferent nerves. The transition from the double-stance phase to the swing phase is controlled by two hand switches used by the therapist or built into the handles of the walking frame for using by the patient. A twenty-five years old male was with a T9/T9 spinal cord injury due to a traffic accident and admitted to Yonsei Rehabilitation Hospital for comprehensive treatment. After 30 days of training using the Parastep(R) he was able to stand for 10 minutes. After 43 days, he was able to walk and at discharged he could walk for 100 meters.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2361-2368
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• 2015

Objective: To evaluate the diagnostic accuracy of contrast-enhanced ultrasonography (CEUS) in differentiating between benign and malignant enlarged lymph nodes using meta-analysis. Materials and Methods: Pubmed, Embase, SCI and Cochrane databases were searched for studies (up to September 1, 2014) reporting the diagnostic performance of CEUS in discriminating between benign and malignant lymph nodes. Inclusion criteria were: prospective study; histopathology as the reference standard; and sufficient data to construct $2{\times}2$ contingency tables. Methodological quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). Patient clinical characteristics, sensitivity and specificity were extracted. The summary receiver operating characteristic curve was used to examine the accuracy of CEUS. A meta-analysis was performed to evaluate the clinical utility in identification of benign and malignant lymph nodes. Sensitivity analysis was performed after omitting outliers identified in a bivariate boxplot and publication bias was assessed with Egger testing. Results: The pooled sensitivity, specificity and AUROC were 0.92 (95%CI, 0.85-0.96), 0.91 (95%CI, 0.82-0.95) and 0.97 (95%CI, 0.95-0.98), respectively. After omitting 3 outlier studies, heterogeneity decreased. Sensitivity analysis demonstrated no disproportionate influences of individual studies. Publication bias was not significant. Conclusions: CEUS is a promising diagnostic modality in differentiating between benign and malignant lymph nodes and can potentially reduce unnecessary fine-needle aspiration biopsies of benign nodes.

• Journal of the Korean Institute of Oriental Medical Informatics
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• v.11 no.2
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• pp.23-31
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• 2005

Central cord syndrome (CCS) is the most common incomplete spinal cord injury (SCI) syndrome, occured by cervical hyperextension injury. It is characterized by disproportionately greater motor impairment in the upper extremities compared to the lower extremities, bladder dysfunction, and variable degrees of sensory loss below the level of injury. Recently 36 year-old male was admitted with upper motor neuron weakness, sensory loss in the upper extremities and stiff neck. We report the improvement of his symptoms through both western medical treatment and oriental medical treatment.

• Physical Therapy Rehabilitation Science
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• v.11 no.2
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• pp.235-244
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• 2022

Objective: The aim of this study was to investigate of the foot plantar pressure and usability after gait training using the ExoAtlet wearable exoskeleton robot in an incomplete spinal cord injury (SCI) patient. Design: A case study Methods: Six participants with an asymmetry in motor and sensory function completed the gait training using ExoAtlet wearable exoskeleton robot for 15 sessions, five per weeks, 3weeks. They were divided into two groups (low and high strength group) and group differences were evaluated about session at stating of gait, gait distance at final session and foot plantar pressures and useability after training. Results: Low strength group was faster than high strength group on adaptation of robot gait. And high strength group increased faster than low strength group on the gait distance during training. In standing and gait, weaker leg was higher than stronger leg on mean foot plantar pressure in low strength group. And stronger leg was higher than weaker leg on foot plantar pressure in high strength group. The length of the anterior-posterior trajectory of the center of pressure during gait was similar in low strength group, but different in high strength group. useability was positive about ExoAtlet wearable exoskeleton gait after training. Conclusions: ExoAtlet wearable exoskeleton robot gait training was positive about improving gait in all participants regardless of differences in severity of symptoms and gait abnormalities.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.4
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• pp.429-434
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• 2012

This paper presents a technology for manipulating external devices by Brain Computer Interface (BCI) system. Recently, BCI based rehabilitation and assistance system for disabled people, such as patient of Spinal Cord Injury (SCI), general paralysis, and so on, is attracting tremendous interest. Especially, electroencephalogram (EEG) signal is used to organize the BCI system by analyzing the signals, such as evoked potential. The general findings of neurophysiology support an availability of the EEG-based BCI system. We concentrate on the event-related synchronization of motor imagery EEG signal, which have an affinity with an intention for moving control of external device. To analyze the brain activity, short-time Fourier transform and particle swarm optimization are used to optimal feature selection from the preprocessed EEG signals. In our experiment, we can verify that the power spectral density correspond to range mu-rhythm(${\mu}8$~12Hz) have maximum amplitude among the raw signals and most of particles are concentrated in the corresponding region. Result shows accuracy of subject left hand 40% and right hand 38%.