• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37B no.9
• /
• pp.787-794
• /
• 2012

The visible light communication is considered as a next generation communication technology, when utilizes LED and PD for communication. Since it is easy to provide LOS communication environment along with cheap deployment cost, the positioning system based on VLC has been actively studied. However, the existing positioning system using VLC requires a complex computation and an additional deployment cost due to sensors for example. In this paper, we propose a new positioning system based on VLC which does not require additional complexity and the cost. In addition, the procedure for operating LED panels for positioning and the recognition schemes of pilot signal are proposed. The performance of recognition schemes of pilot signal is analyzed through the computer simulations.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.2A
• /
• pp.119-127
• /
• 2012

In this paper a super-resolution time delay estimation algorithm is developed for real-time locating systems (RTLSs) that employ a direct-sequence spread spectrum technique, along with its performance analysis in multipath environments. The classical correlation method provides relatively good performance in line-of-sight (LOS) environments but its performance seriously degrades in multipath environments, especially when signals are spaced closer than a PN chip. Therefore we shall develop a super-resolution time delay estimation algorithm that may estimate the time delays of multipath signals even in closely spaced multipath environments using the MUSIC algorithm for direction-of-arrival estimation and analyze its performance by applying the algorithm to the ISO/IEC 24730-2.1 RTLS system. 

• Journal of Digital Convergence
• /
• v.11 no.10
• /
• pp.549-556
• /
• 2013

In this study, we investigated the effects of stretching and movement with mobilization in lunge position on the muscle activity of the lower limb and limited of stability in chronic stroke patients with hemiplegia. Sixteen subjects were randomly selected and classified into the experimental and control groups. The experimental group performed self stretching exercises in the lunge position, and in the control group performed movement with mobilization in the lunge position. The interventions were conducted for 20 min, 5 times a week for 8 weeks. Statistical analyses were performed using repeated ANOVA. The analysis results showed no statistically significant between-group differences with respect to the muscle activity(%MVIC;maximum voluntary isometric contraction) of lower limb and limited of stability(LOS)(p>.05). However, statistically significant within-group differences were observed in the maximum voluntary isometric contraction and limited of stability for both the groups (p<.05). Therefore, self stretching in the lunge position is considered to have positive influences on the muscle strength and balance in stroke patients with hemiplegia.

• Journal of Digital Convergence
• /
• v.17 no.12
• /
• pp.243-248
• /
• 2019

Multi-Task Learning(MTL) is a training method that trains a single neural network with multiple tasks influences each other. In this paper, we compare performance of MTL Named entity recognition(NER) model trained with Korean traditional culture corpus and other NER model. In training process, each Bi-LSTM layer of Part of speech tagging(POS-tagging) and NER are propagated from a Bi-LSTM layer to obtain the joint loss. As a result, the MTL based Bi-LSTM model shows 1.1%~4.6% performance improvement compared to single Bi-LSTM models.

• Journal of Korean Society of Transportation
• /
• v.15 no.4
• /
• pp.143-163
• /
• 1997

Incident management is significant far the traffic management systems. The management of incidents determines the smoothness of freeway operations. The dynamic nature of incidents and the uncertainty associated with them require solutions based on the incident operator's judgment. Fuzz systems attempt to adapt such human expertise and are designed to replicate the decision making capability of on operator. Fuzzy systems process complex traffic information, and transmit it in a simplified, understandable form to human traffic operators. In this study, fuzzy rules were developed based on data from real incidents on Santa Monica Freeway in LosAngeles. The fuzzy rules ail linguistic based, and hence, user-friendly. A comparison of the results from the linguistic model with the real incident durations indicate that the outputs from the model reliably correspond to real incident durations conditions. The model reliably predicts the freeway incident duration. The modes can thus be used as an effective management tool for freeway incident response systems. The approach could be applied to other problems regarding dispatch systems in transportation.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.8 no.1
• /
• pp.203-210
• /
• 2004

The fragility curves of seismic retrofitted bridges by steel jacketing at bridge columns and restrainers at expansion joints after the 1994 Northridge earthquake are developed. Fragility curves are represented by lognormal distribution functions with two parameters (median and log-standard deviation) and developed as a function of peak ground acceleration(PGA). Two parameters in the lognormal distribution are estimated by the maximum likelihood method. The sixty ground acceleration time histories for Los Angeles area developed for FEMA SAC project are used for the dynamic analysis of bridges. The comparison of fragility curves of the bridges before and after column retrofit demonstrates that the improvement of the bridges with steel jacketing on the seismic performance is excellent for the damage states defined in this study. The comparison of fragility curves of the bridges before and after the installation of restrainers at expansion joints also shows the improvement in the seismic performance of restrained bridges for the severe damage state.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.13 no.4
• /
• pp.20-29
• /
• 2014

Density is applied both three major macroscopic traffic variables (traffic volume, speed, and density) and two measures of effectiveness (MOE) for level of service (LOS) on highway (density and V/C). Especially, it is known for the most accurate MOE on evaluating the LOS of highway. Despite such importance, there is a lack of study on density relatively than other variables for its difficulty of measurement. Existing density estimation methods have some limitations such as density values of same traffic flow vary with collecting time. In this study, we researched actual density measuring method with panoramic image, after each CCTV images in the Sapaesan Tunnel on Seoul Ring Expressway are matched into one panoramic image. Analysis through the Central Limit Theorem shows that density of 24 1 km-images, which means 24 second, applies traffic situation well. That is to say that reasonable density value regardless of collecting time, and practical density which represents actual traffic flow can be taken in case of measuring density by suggested collecting cycle.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.18 no.2
• /
• pp.94-101
• /
• 2020

Purpose: This study examined the clinical and epidemiological characteristics of intensive care unit (ICU) patients admitted or died in the emergency medical center with acute-poisoning to investigate the variables related to the prognosis. Methods: The data were collected from poisoning patients admitted or died in the emergency medical center of a general hospital located in Seoul, from January 2014 to February 2020. The subjects of this study were 190 patients. The medical records were screened retrospectively, and the clinical and epidemiological characteristics of the patients in the emergency room (ER) and ICU were examined to investigate the contributing factors that influence the poor prognosis. Results: The study analyzed 182 patients who survived after being admitted to the intensive care unit (ICU). The results are as follows. The mental change (87.4%) was the most common symptom. Sedative poisoning (49.5%) was the commonest cause. For most patients, pneumonia (26.9%) was the most common complication. Hypotension (23.7%), tachycardia (42.1%), fever (15.8%), seizures (10.5%), dyspnea (2.6%), high poisoning severity score (PSS), type of toxic material, mechanical ventilator application (39.5%), inotropes application (39.5%), and pneumonia (55.3%) were correlated the LOS over 5 days in the ICU. 8 patients died. In the case of death pesticides and carbon monoxide were the main toxic materials; tachycardia, bradycardia, and hypotension were the main symptoms, and a mechanical ventilator and inotropes were applied. Conclusion: Patients with unstable vital signs, high PSS, and non-pharmaceutical poisoning had a prolonged LOS in the ICU and a poor prognosis.

• Health Policy and Management
• /
• v.3 no.1
• /
• pp.53-83
• /
• 1993

A small number of high cost patients usually spend a larger proportion of scarce health resources. Korea is no exception. Under the national health insurance, 12% of the insured persons have consumed approximately half of the national health insurance expenditures. Therefore, it is necessary to identify the characteristics of the high cost patient group, if we would like to reduce them. This study has defined high cost patients as those who have spent one and half million won and over per 6 months. The study reveals that high cost users are those who have a longer length of stays(LOS), 40days of LOS in the 6 months, have multiple admissions, 2 to 3 admissions per 6 months and are the elderly patients. They have spent 814.126won per on the average, and commonly suffered from malignant neoplasms, circulatory diseases, fracture, diabetes mellitus, etc. Unlike the case of western developed countries, early readmissions are not the major causes of high cost spending in Korea. Undoubtedly, a lengthy admission is the main cause of large spending. Health policies should vigorously be explored to respond appropriately. There are evidences that hospital beds are often misused. As the Korean health care system is lacking in a mechanism of patient evaluation under the fee-for-service remuneration system, an idea of progressive patient care needs to be tested. The Goverment should set up health policy to diversify the role of long-term care facilities and encourage people to establish them. Further studies are needed to identify factors influencing large medical bills necessary for formulating the health policy on cost containment.

• Clinics in Shoulder and Elbow
• /
• v.26 no.2
• /
• pp.140-147
• /
• 2023

Background: The management of acromioclavicular (AC) joint dislocation remains controversial. Recently, anatomic coracoclavicular (CC) fixation with a double clavicular tunnel and three flip-buttons has shown promising results. This study aimed to evaluate functional and radiological outcomes in patients with high-grade AC joint dislocation treated with anatomic CC fixation using double clavicular tunnels and three flip-buttons. Methods: A retrospective, unicentric study was performed. The study included patients with high-grade AC joint dislocation who underwent surgery with anatomic CC fixation using double clavicular tunnels and three flip-buttons. Demographic data were obtained from medical records. A functional evaluation using subjective shoulder value (SSV), visual analog scale (VAS), and disabilities of the arm, shoulder, and hand (DASH) questionnaires was performed, and an evaluation of preoperative and postoperative comparative Zanca view images was performed. Factors associated with functional outcomes and radiological AC reduction were analyzed. Results: A total of 83 patients completed follow-up and were included in the analysis. The mean SSV, VAS, and DASH scores were 92.8, 0.8, and 6.4, respectively. Patients who had complications experienced significantly worse functional outcomes (DASH: P=0.037). Suboptimal final AC reduction was observed in nine patients (11.1%), and significantly more frequently in patients older than 40 years (P=0.031) and in surgeries performed more than 7 days after injury (P=0.034). There were two reoperations (2.4%). Conclusions: Anatomic CC fixation with a double clavicular tunnel and three flip-buttons leads to good functional outcomes, low complication rates, and high rates of optimal AC reduction.