Modified Unscented Kalman Filter for a Multirate INS/GPS Integrated Navigation System

Munkhzul Enkhtur,조성윤,김경호 한국전자통신연구원 2013 ETRI Journal Vol.35 No.5

Instead of the extended Kalman filter, the unscented Kalman filter (UKF) has been used in nonlinear systems without initial accurate state estimates over the last decade because the UKF is robust against large initial estimation errors. However, in a multirate integrated system, such as an inertial navigation system (INS)/Global Positioning System (GPS) integrated navigation system, it is difficult to implement a UKF-based navigation algorithm in a low-grade or mid-grade microcontroller, owing to a large computational burden. To overcome this problem, this letter proposes a modified UKF that has a reduced computational burden based on the basic idea that the change of probability distribution for the state variables between measurement updates is small in a multirate INS/GPS integrated navigation filter. The performance of the modified UKF is verified through numerical simulations.

개발도상국의 전자상거래 기반구축 방안

네르규 문크졸(Munkhzul Nergui),김동수(Dongsoo Kim) 한국전자거래학회 2009 한국전자거래학회지 Vol.14 No.4

최근 몽골과 같은 개발도상국에서는 인터넷 기반의 전자상거래 인프라를 구축하기 위해 노력하고 있다. 본 연구에서는 개발도상국 가운데 인터넷 활용이 증가하고 있는 몽골에서 전자상거래를 활성화시키기 기반구축 방안을 제시하였다. 몽골의 전자상거래 현황 및 문제점을 조사?분석하고, 웹기반 설문조사를 통해 몽골 소비자들의 전자상거래 인식도 및 소비자 행동을 분석하였다. 또한 한국 등 전자상거래가 활발한 국가의 전자상거래 정책 및 현황을 벤치마킹하여, 개발도상국가인 몽골 전자상거래의 문제점 해결을 위한 정책 방향을 제안하였다. 몽골 소비자들이 전자상거래를 원활히 수행하는데 도움이 되도록 본 연구에서 파악된 개선 방향을 반영한 인터넷 쇼핑몰을 구축하였다. 본 연구의 결과는 몽골과 같은 개발도상국에서 전자상거래를 확산시키기 위한 구체적인 정부 정책을 수립하는데 도움을 줄 수 있을 것으로 예상된다. Recently, developing countries such as Mongolia are trying to establish Internet-based e-Commerce infrastructures. This paper aims to propose methods for establishing e-Commerce infrastructure in Mongolia where the usage rate of the Internet are growing. At first, current situation of e-Commerce in Mongolia has been analyzed. In addition, public opinion on this sector and consumer behavior have been researched in order to define the problems and issues. Government policies of the countries including Korea, where the level of e-Commerce development is high, were benchmarked and a strategic plan has been developed to resolve the issues. Finally, for the purpose of making e-Commerce widely adopted by Mongolian people, we have developed an Internet shopping mall which can solve the issues identified in this paper. It is expected that the results of this research could help the Government of Mongolia establish policies for supporting e-Commerce development.

차량용 증강현실을 위한 AMRHKF 필터 기반 복합항법 기술

조성윤,Munkhzul Enkhtur,김경호 제어로봇시스템학회 2012 제어로봇시스템학회 국내학술대회 논문집 Vol.2012 No.4

Preliminary Results on Soil Study in Case of Mongolia

Azzaya, Dolgorsuren,Munkhzul, Dorjsuren,Norov, Nanzad,Batkhishig, Ochirbat Korea Association For Quaternary Research 2007 제사기학회지 Vol.21 No.2

P2P Ranging-Based Cooperative Localization Method for a Cluster of Mobile Nodes Containing IR-UWB PHY

조성윤,김주영,Munkhzul Enkhtur 한국전자통신연구원 2013 ETRI Journal Vol.35 No.6

The problem of pedestrian localization using mobile nodes containing impulse radio ultra wideband (IR-UWB) is considered. IEEE 802.15.4a-based IR-UWB can achieve accurate ranging. However, the coverage is as short as 30 m, owing to the restricted transmit power. This factor may cause a poor geometric relationship among the mobile nodes and anchor nodes in certain environments. To localize a group of pedestrians accurately, an enhanced cooperative localization method is proposed. We describe a sequential algorithm and define problems that may occur in the implementation of the algorithm. To solve these problems, a batch algorithm is proposed. The batch algorithm can be carried out after performing the sequential algorithm to linearize the nonlinear range equation. When a sequential algorithm cannot be performed due to a poor geometric relationship among nodes, a batch algorithm can be carried out directly. Herein, Monte Carlo simulations are presented to illustrate the proposed method and verify its performance.

인프라 없는 실내 공간에서 소방관 위치추정 기술

조성윤,최영우,Munkhzul Enkhtur,박상준 제어로봇시스템학회 2010 제어로봇시스템학회 국내학술대회 논문집 Vol.2010 No.5

Optimal Social Distancing Policy for COVID-19 Control in Korea: A Model-Based Analysis

Youngji Jo,Sourya Shrestha,Munkhzul Radnaabaatar,Hojun Park,Jaehun Jung 대한의학회 2022 Journal of Korean medical science Vol.37 No.23

Background: Since March 2020, when coronavirus disease 2019 (COVID-19) was declared a pandemic, many countries have applied unprecedented restrictive measures to contain the spread of the virus. This study aimed to explore the optimal social distancing policy for COVID-19 control in South Korea to safely reopen the society. Methods: We developed an age-specific, deterministic compartment epidemic model to examine the COVID-19 control decision-making process, including the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between 1 July 2021 and 30 December 2022. The model consists of the natural history of COVID-19, testing performance, vaccinations, and social distancing enforcement measures to detect and control SARS-CoV-2. We modelled potential intervention scenarios with three distinct components: 1) social distancing duration and level; 2) testing intensity; and 3) vaccination uptake rate. The primary and secondary outcomes were COVID-19 incidence and prevalence of severe patients requiring intensive care unit (ICU) care. Results: Four (or more) months of social distancing (that can reduce 40–60% transmission) may mitigate epidemic resurgence and ICU demand in the future and keep the cases below the capacity limit if the testing intensity and vaccination rate remain constant or increase by 20% (with respect to the current level). In contrast, two months of strict social distancing enforcement may also successfully mitigate future epidemic surge and ICU demand as long as testing intensity and vaccination rates are increased by 20%. Conclusion: In South Korea, given the relatively high vaccination coverage and low incidence, four or more months of social distancing enforcement can effectively mitigate epidemic resurgence after lifting the social distancing measures. In addition, increasing the testing intensity and vaccination rate may help reduce necessary social distancing levels and duration to prevent a future epidemic resurgence and mitigate social and economic damage.

The Impact of Entry Restrictions on the Spread of Severe Acute Respiratory Syndrome Coronavirus Variants Between 2021 and 2022

Hong Jinwook,Park Ae Kyung,Radnaabaatar Munkhzul,Kim Eun-Jin,Kim Dong Wook,Jung Jaehun 대한의학회 2023 Journal of Korean medical science Vol.38 No.28

To contain the surge of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the South Korean government has implemented non-pharmacological interventions as well as border restrictions. The efficacy of entry restrictions should be evaluated to facilitate their preparation for new variants of SARS-CoV-2. This study explored the impact of border policy changes on overseas entrants and local cases of SARS-CoV-2 variants. Data from the Korea Disease Control and Prevention Agency randomly collected between April 11, 2021 and August 20, 2022 were evaluated using the Granger causality model. The results showed that the outbreak gap of delta variants between international and domestic cases was 10 weeks, while that of omicron variants was approximately 2 weeks, meaning that the quarantine policy helped contain delta variants rather than more transmissible variants. It is recommended that countries implement quarantine policies based on particular purposes accounting for the specific features of different variants to avoid potential negative impacts on the economy.

Overweight and Obesity Are Risk Factors for Coronavirus Disease 2019: A Propensity Score-Matched Case-Control Study

지원준,이예린,허경민,강민선,황인철,Munkhzul Radnaabaatar,이대호,정재훈 대한내분비학회 2021 Endocrinology and metabolism Vol.36 No.1

Although obesity is a risk factor for infection, whether it has the same effect on coronavirus disease 2019 (COVID-19) need confirming. We conducted a retrospective propensity score matched case-control study to examine the association between obesity and COVID-19. This study included data from the Nationwide COVID-19 Registry and the Biennial Health Checkup database, until May 30, 2020. We identified 2,231 patients with confirmed COVID-19 and 10-fold-matched negative test controls. Overweight (body mass index [BMI] 23 to 24.9 kg/m2; adjusted odds ratio [aOR], 1.16; 95% confidence interval [CI], 1.1.03 to 1.30) and class 1 obesity (BMI 25 to 29.9 kg/m2; aOR, 1.27; 95% CI, 1.14 to 1.42) had significantly increased COVID-19 risk, while classes 2 and 3 obesity (BMI ≥30 kg/m2) showed similar but non-significant trend. Females and those <50 years had more robust association pattern. Overweight and obesity are possible risk factors of COVID-19.

Model-based cost-effectiveness analysis of oral antivirals against SARS-CoV-2 in Korea

Jo Youngji,Kim Sun Bean,Radnaabaatar Munkhzul,Huh Kyungmin,Yoo Jin-Hong,Peck Kyong Ran,Park Hojun,정재훈 한국역학회 2022 Epidemiology and Health Vol.44 No.-

OBJECTIVES: Many countries have authorized the emergency use of oral antiviral agents for patients with mild-to-moderate cases of coronavirus disease 2019 (COVID-19). We assessed the cost-effectiveness of these agents for reducing the number of severe COVID-19 cases and the burden on Korea’s medical system. METHODS: Using an existing model, we estimated the number of people who would require hospital/intensive care unit (ICU) admission in Korea in 2022. The treatment scenarios included (1) all adult patients, (2) elderly patients only, and (3) adult patients with underlying diseases only, compared to standard care. Based on the current health system capacity, we calculated the incremental costs per severe case averted and hospital admission for each scenario. RESULTS: We estimated that 236,510 COVID-19 patients would require hospital/ICU admission in 2022 with standard care only. Nirmatrelvir/ritonavir (87% efficacy) was predicted to reduce this number by 80%, 24%, and 17% when targeting all adults, adults with underlying diseases, and elderly patients (25, 8, and 4%, respectively, for molnupiravir, with 30% efficacy). Nirmatrelvir/ritonavir use is likely to be cost-effective, with predicted costs of US$8,878, US$8,964, and US$1,454, per severe patient averted for the target groups listed above, respectively, while molnupiravir is likely to be less cost-effective, with costs of US$28,492, US$29,575, and US$7,915, respectively. CONCLUSIONS: In Korea, oral treatment using nirmatrelvir/ritonavir for symptomatic COVID-19 patients targeting elderly patients would be highly cost-effective and would substantially reduce the demand for hospital admission to below the capacity of the health system if targeted to all adult patients instead of standard care.