• Parasites, Hosts and Diseases
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• v.59 no.2
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• pp.131-138
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• 2021

Helminth infections are prevalent in Lao People's Democratic Republic (Lao PDR). This study aimed at determining the prevalence and risk factors of intestinal helminthiasis in remote mountainous villages of northern Lao PDR. During the dry season in January 2017, a cross-sectional survey was conducted in 3 remote mountainous villages in Oudomxay province, Lao PDR. Villagers older than 18 years of age who agreed to submit stool samples or undergo an interview, were recruited. Stool samples from 198 individuals were examined by the Kato-Katz method, and a questionnaire surveyed 161 individuals among them. Univariable and multivariable logistic regression analyses were used to identify risk factors associated with the intestinal helminthiasis. An overall prevalence of intestinal helminthiasis was 75.8%. Hookworm infection was the most common (63.1%), followed by Opisthorchis viverrini/minute intestinal flukes (17.7%), Taenia spp. (15.2%), Trichuris trichiura (2.0%), Ascaris lumbricoides (1.5%), and Enterobius vermicularis (1.0%). Questionnaire analysis revealed sex (male) and absence of latrine to be significant risk factors for hookworm infection and consumption of raw meat for taeniasis. These results suggest that the mountainous area in northern Lao PDR has a different composition of helminth infections from other studies conducted in Lao PDR; a high prevalence of hookworm infection and taeniasis and low prevalence of T. trichiura and A. lumbricoides infections were observed. Also, liver flukes or intestinal flukes were similarly prevalent in the mountainous area.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.11
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• pp.1189-1195
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• 2008

We introduce a MEMS-based pedestrian dead reckoning (PDR) system. A walking navigation algorithm for pedestrians is presented and map-matching algorithm for the navigation system based on dead reckoning (DR) is proposed. The PDR is equipped on the human body and provides the position information of pedestrians. And this is able to be used in ubiquitous sensor network (USN), U-hearth monitoring system, virtual reality (VR) and etc. The PDR detects a step using a novel technique and simultaneously estimates step length. Also an azimuth of the pedestrian is calculated using a fluxgate which is the one of magnetometers. Map-matching algorithm can be formulated to integrate the positioning data with the digital road network data. Map-matching algorithm not only enables the physical location to be identified from navigation system but also improves the positioning accuracy. However most of map-matching algorithms which are developed previously are for the car navigation system (CNS). Therefore they are not appropriate to implement to pedestrian navigation system based on DR system. In this paper, we propose walking navigation system and map-matching algorithm for PDR.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.2
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• pp.49-58
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• 2019

A number of techniques have been studied to estimate the position of pedestrians in indoor space. Among them, the technique of estimating the position using only the sensors attached to the body of the pedestrian without using the infrastructure is regarded as a very important technology for special purpose pedestrians such as the firefighters. In particular, it forms a research field under the name of Pedestrian Dead Reckoning (PDR). In this paper, we focus on a method for step detection which is essential when performing PDR using Inertial Measurement Unit (IMU) mounted on a shoe. Many researches have been done to detect the stance phase where the foot contacts the ground. Most of these methods, however, have a way to detect the specific size of the sensor signal and require thresholds for these methods. This has the difficulty of changing these thresholds if the user is different. To solve this problem, we propose a stance phase detection method that does not require any threshold value. It is expected that this result will make it easier to commercialize the technology because PDR can be implemented without user-dependent parameter setting.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.1
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• pp.35-44
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• 2022

In this paper, a dual foot (DF)-PDR system is proposed for the fusion of integration (IA)-based PDR systems independently applied on both shoes. The horizontal positions of the two shoes estimated from each PDR system are fused based on a particle filter. The proposed method bounds the position error even if the walking time increases without an additional sensor. The distribution of particles is a non-Gaussian distribution to express the lateral error due to systematic drift. Assuming that the shoe position is the pedestrian position, the multi-modal position distribution can be fused into one using the Gaussian sum. The fused pedestrian position is used as a measurement of each particle filter so that the position error is corrected. As a result, experimental results show that position of pedestrians can be effectively estimated by using only the inertial sensors attached to both shoes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.12
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• pp.54-61
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• 2011

We propose a surveillance-alert system based on optimal placements of PDR(Pulsed Doppler Radar) sensors in USN. By using the detection information of moving target from PDR sensor and by considering the covered detection region and geographical property of the strategic area, three optimal placements of sensors are proposed. The proposed placement are named as the grid type, the linear type and the zigzag type. Also, the surveillance alert system based on three sensor placements are developed. The alert level of the proposed surveillance-alert system are 'Perception', 'Caution', 'Warning' and 'Danger' which are decided by the distance change between the moving targets and the command post. The performace of the developed system is verified via outdoor experiments.

• Parasites, Hosts and Diseases
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• v.50 no.3
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• pp.269-272
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• 2012

Echinostome eggs were detected in 22 (1.1%) of 2,074 people residing in riparian villages along the Mekong River in Khammouane Province, Lao PDR. In order to recover the adult flukes, 9 persons were treated with praziquantel and purged with magnesium salts. A total of 55 echinostome specimens (4 species) were recovered from the 9 persons. Echinostoma revolutum (8 specimens) was recovered from 3 persons, Artyfechinostomum malayanum (8 specimens) was from 2 persons, Echinochasmus japonicus (33 specimens) was from 7 persons, and Euparyphium sp. (6 specimens) was from 1 person. In Lao PDR, only human infections with E. japonicus were previously known. Therefore, the present study describes human infections with E. revolutum, A. malayanum, and Euparyphium sp. for the first time in Lao PDR. These results indicate that the surveyed villages of Khammouane Province, Lao PDR are low-grade endemic foci of echinostomiasis.

• Korean Journal of Plant Taxonomy
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• v.46 no.4
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• pp.348-355
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• 2016

We report previously unrecognized flowering plants of Lao PDR found during a botanical survey of Lao PDR in 2015-2016. We found Phyllagathis tuberosa (C. Hansen) Cellinese & S. S. Renner (Melastomataceae) and Tolypanthus pustulatus Barlow (Loranthaceae) in the Phou Khao Khouay National Biodiversity Conservation Area (PKKNBCA), previously only known from type localities in Thailand. This is the first report of Phyllagathis tuberosa and the genus Tolypanthus in the Lao PDR. We also found Lonicera bournei Hemsl. (Caprifoliaceae) in the proposed Phosabous National Protected Area (PNPA) of Xiangkhoang, neglected with regard to the flora of Laos since its initial report in early 20th century. The current report will augment our understanding of the floristic relationships among SE Asian countries and will help elucidate the biodiversity of Lao PDR.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.271-280
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• 2023

Pedestrian Dead Reckoning (PDR) methods using initial sensors are being studied to provide the location information of smart device users in indoor environments where satellite signals are not available. PDR can continuously estimate the location of a pedestrian regardless of the walking environment, but has the disadvantage of accumulating errors over time. Unlike this, WiFi signal-based wireless positioning technology does not accumulate errors over time, but can provide positioning information only where infrastructure is installed. It also shows different positioning performance depending on the environment. In this paper, an integrated positioning technology integrating two positioning techniques with different error characteristics is proposed. A technique for correcting the error of PDR was designed by using the location information obtained through WiFi Measurement-based fingerprinting as the measurement of Extended Kalman Filte (EKF). Here, a technique is used to variably calculate the error covariance of the filter measurements using the WiFi Fingerprinting DB and apply it to the filter. The performance of the proposed positioning technology is verified through an experiment. The error characteristics of the PDR and WiFi Fingerprinting techniques are analyzed through the experimental results. In addition, it is confirmed that the PDR error is effectively compensated by adaptively utilizing the WiFi signal to the environment through the EKF to which the adaptive error covariance proposed in this paper is applied.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5435-5440
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• 2013

Background: Recent estimates suggest that in the Lao People's Democratic Republic (Lao PDR) the burden of cancer in terms of DALYs lost is amongst the highest in South East Asia. As such, increasingly cancer is becoming an important public health concern in the country. Lao PDR however has no population-based cancer registry and only one hospital-based registry. Cancer treatment within the country is extremely limited. Patients who can, may travel to neighboring countries for treatment, but little information about this is available in the country. The aim of this study was to estimate some of the otherwise largely unknown parameters of the cancer burden in Lao PDR. Materials and Methods: This is a retrospective, descriptive study based on the records of 847 Lao cancer cases treated with surgery, radiation and chemotherapy at Srinagarind Hospital, Khon Kaen University, in Thailand between 1988 and 2010. Results: The annual rate of registration of Lao cancer cases fluctuated, but showed an increasing trend. Most cancers were diagnosed by histology (65.2%), and a combination of endoscopy and radiology (15.6%). In most cases (70.2%) the stage of cancer at diagnosis could not be determined. In those whose stage could be identified, 54.0% were at the final stage (Stage IV). Among males, the commonest cancer sites were the liver (16.1%), blood (12.3%) and nasopharynx (10.6%). Those in female patients were the cervix (22.2%), breast (14.6%) and blood (8.1%). Conclusions: This study indicates that despite some fluctuations, the number of Lao cancer patients presenting at Srinagarind Hospital, Khon Kaen, gradually increased between 1988 and 2010. The unfavorable pattern of late-stage cancer diagnosis among male and female patients suggests a need for cancer control interventions and the establishment of cancer registration and treatment facilities within Lao PDR.