• Journal of Korean Society of Disaster and Security
• /
• v.9 no.1
• /
• pp.33-38
• /
• 2016

Real time location system was development for safety management at road and bridge maintenance field. The system can check the real-time location detection, movement history, behavior of a number of laborers. The system consisted of a Bluetooth and ZigBee that uses low-power. It had a very large error that the previous method for the position recognition by triangulation using the RSSI. Because This study proposed a new distance measurement and correction scheme using RSSI and accelerometer. It was evaluated in the maintenance field. A development system were evaluated in the field, the results are shown an error between 0.2 m and 0.4 m. And through the acceleration of history it was confirmed by determining possible to determine the safety situation of the laborers.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.6
• /
• pp.1241-1248
• /
• 2019

In this paper, an auxiliary device was implemented to help blind people more safely from obstacles or risk factors while walking. The ultrasonic sensors detect obstacles in the front, so that the noise gap and the vibration intensity of the buzzer can be heard differently by distance and angle, and so the situation can be perceived by pedestrians. When the ambient light becomes darker than the light intensity set using the CdS resistance value of the light sensor, the LED automatically turns on, makes it easier for pedestrians to recognize the position of the auxiliary device through buzzer if the pedestrian misses the aid using the gyro sensor's slope. Moreover, the location and situation of the blind were transmitted to the caregiver to check safety and behavior using GPS and Bluetooth.

• The KIPS Transactions:PartB
• /
• v.13B no.4 s.107
• /
• pp.463-470
• /
• 2006

It is difficult to track and extract the movement of an object through a camera exactly because of noises and changes of the light. The fast searching algorithm is necessary to extract the object and to track the movement for realtime image. In this paper, we propose the correct and fast algorithm using the variable searching area and the background image change method to robustic for the change of background image. In case the threshold value is smaller than reference value on an experimental basis, change the background image. When it is bigger, we decide it is the point of the time of the object input and then extract boundary point of it through the pixel check. The extracted boundary points detect precise movement of the object by creating area block of it and searching block that maintaining distance. The designed and embodied system shows more than 95% accuracy in the experimental results.

• Atmosphere
• /
• v.21 no.4
• /
• pp.337-347
• /
• 2011

In this paper, we developed a detection and correction method of noisy pixels embedded in the time series of normalized difference vegetation index (NDVI) data based on the spatio-temporal continuity of vegetation conditions. For the application of the method, 25-year (1982-2006) GIMMS (Global Inventory Modeling and Mapping Study) NDVI dataset over the Korean peninsula were used. The spatial resolution and temporal frequency of this dataset are $8{\times}8km^2$ and 15-day, respectively. Also the land cover map over East Asia is used. The noisy pixels are detected by the temporal continuity check with the reference values and dynamic threshold values according to season and location. In general, the number of noisy pixels are especially larger during summer than other seasons. And the detected noisy pixels are corrected by the iterative method until the noisy pixels are completely corrected. At first, the noisy pixels are replaced by the arithmetic weighted mean of two adjacent NDVIs when the two NDVI are normal. After that the remnant noisy pixels are corrected by the weighted average of NDVI of the same land cover according to the distance. After correction, the NDVI values and their variances are increased and decreased by 5% and 50%, respectively. Comparing to the other correction method, this correction method shows a better result especially when the noisy pixels are occurred more than 2 times consistently and the temporal change rates of NDVI are very high. It means that the correction method developed in this study is superior in the reconstruction of maximum NDVI and NDVI at the starting and falling season.

• Journal of Broadcast Engineering
• /
• v.15 no.6
• /
• pp.731-741
• /
• 2010

In this paper, we propose the methodology of prediction of field strength for a digital television (DTV) receiver by virtue of Recommendation ITU-R P.1546. The curves shown in this recommendation represent the point-to area field strength for 1.0 kW effective radiated power in the 30 MHz ~ 3000 MHz. Based upon the procedures described in this Recommendation, computation results are presented here from the derived formulation of field strength for DTV receiver. To show the validity of this method, some results are compared with the analysis by Okumura-Hata model and it was shown that the error of field strength is in the range of 6.9 ~ 11.5 %. The presented method provides not only the predicted values of field strength for DTV receiving area to check the quality of transmitted signal, but also an appropriate site selection for obtaining good propagation environment. In addition, it can be directly used for analyzing the protection ratio or separated distance for frequency sharing in the same band.

• Journal of Oral Medicine and Pain
• /
• v.20 no.2
• /
• pp.489-496
• /
• 1995

The purpose of this study was to evaluate an effect of change on head posture initial occlusal contacts with measuring the distances between initial occlusal contacts and maximum intercuspal position at different head posture in TMDs patient. For this study, 24 patients from age 13 to 36 were selected, they were examined health history taken, patients who have sign and symptoms of TMDs were examine before the study. For the normal group, 21 adults from age 23 to 25 were selected. They have normal or class I molar relationship, and have no other prosthetic restorations. Difference on distance between initial occlusal contact and maximum intercuspal position with mandibular kinesiograph$(MKG^R)$(K6 diagnostic system, Myo-tronic Inc, USA) in upright, supine, 45$^{\circ}$ extension, 30$^{\circ}$ flexion position of the head were measured. The Frankfort horizontal plane was used as a reference plane. The results were as follows : 1. There were significant differences between initial occlusal contacts of the normal and patient group on upright position and 30$^{\circ}$ flexion of the head(p<0.05, p<0.01) 2. The position of the initial occlusal contacts have a tendency to place anterior and inferior to maximal intercuspal position in upright position and 30( flexion of the head as well as posterior and inferior in supine position and 45$^{\circ}$ extension of the head in the normal and patient groups. 3. There were significant differences among the initial occlusal contacts between uptight and supine position; upright and 45$^{\circ}$ extension of the head(p<0.05); supine position and 30$^{\circ}$ flexion of the head, .and 30(flexion and 45$^{\circ}$ extension of the head in the patient group(p<0.01) The result have shown that after treatment on the supine position, it may be necessary to check occlusal contact on the upright position as well ass flexion of the head. It may need careful adjustment in occlusal condition on upright position of TMDs patient.

• Journal of Digital Contents Society
• /
• v.18 no.7
• /
• pp.1457-1464
• /
• 2017

This paper is to introduce the a system which monitors and detects the object position in reinforced the concrete structure using UWB-RF. This system is able to check any changes in the inside of the concrete structure using its penetration and reflection characteristics and it can also numerically measure the position of rebar in the concrete structure. For the verification of the performance of this system, we set up the internal compositions of concrete in 3 different types of test-bed. On the other hand, for the measuring of the location of rebar, which varies depending on the type of structure, the software which shows the distance in the structure were used. The result shows that the position in the concrete could be measured within the tolerance of ${\pm}1{\sim}4mm$ depending on the type of structure in the concrete.

• Journal of Oral Medicine and Pain
• /
• v.20 no.1
• /
• pp.195-204
• /
• 1995

The purpose of this study was to evaluate effect of head posture change on initial occlusal contacts through measuring the distances between initial occlusal contacts and maximum intercuspal position at different head posture. Two special devices were designed and constructed. Mandibular movement replicator was used to assess reliability of the K6 diagnostic system(MKG; Myo-tronic Inc, Seatle, USA) and head posture calibrator was used to maintain the constant head posture during experiment. We measured difference of distance between initial occlusal contact and maximum intercuspal position with MKG in upright, supine, 45 degrees extension, 30 degrees flexion, 30 degrees right and left bending postion of the head. The Frankfurt horizontal plane was used as a reference plane. 21 adults aged from 23 to 25 were selected, who have normal or class I molar relationship, and have no symptoms on TMJ and masticatory muscles, and have restorations less than 3 surfaces on each tooth, and have no other prosthetic restoration. The obtained results were as follows : The mean absolute distances between initial occlusal contact and maximum intercuspal postion were 0.39(0.18mm in the upright position, 0.65(0.37mm in the supine position, 0.59(0.33mm in the 45 degree extension, 0.70(0.53mm in the 30 degrees flexion, 1.12(1.10mm in the 30 degrees right bending and 1.94(0.67mm in the 30 degrees left bending of the head. The positions of the initial occlusal contacts have a tendency to locate anterior, left and inferior to maximal intercuspal position in upright position, posterior and inferior in supine position and 45 degrees extension, anterior and inferior in 30 degrees flexion, right and inferior in 30 degrees right bending, and left and inferior in 30 degrees left bending of the head. There were significant differences among the initial occlusal contacts in each head postures(P<0.0001). Therefore, we need to check initial occlusal contacts in the altered head posture during occlusal analysis and adjustment of occlusal appliance and dental occlusion for diagnosis and treatment of temporomandibular disorder.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.401-408
• /
• 2005

Recently shield TBM tunnellings are being applied to subway construction in Korean cities. Generally these kinds of tunnellings have the problems in the stability of ground such as subsidence because urban subway is constructed in the shallow depth. A sinkhole occurred on the road just above the tunnel during tunneling in Kwangju, so a survey for upper layer of the tunnel was needed. But conventional Ground Probing Radar can't be applicable due to the presence of steel-mesh screen in the shield segment, so no existent geophysical method is applicable in this site. Because the outer surface of each shield segment is electrically insulated, dipole-dipole resistivity method which is popular in engineering site investigation, was tried to this survey for the first time. Specially manufactured flexible ring-type electrodes were installed into the grouting holes at an interval of 2.4 m on the ceiling. The K-Ohm II system which has been developed by KIGAM and tested successfully in many sites, was used in this site. The system consists of 1000Volt-1Ampere constant-current transmitter, optically isolated 24 bit sigma-delta A/D conversion receiver - maximum 12 channel simultaneous measurements, and graphical automatic acquisition software for easy data quality check in real time. Borehole camera logging with circular white LED lighting was also done to investigate the state of the layer. Measured resistivity data lack of some stations due to failing opening lids of holes, shows general high-low trend well. The dipole-dipole resistivity inversion results discriminate (1) one approximately 4 meter diameter cavity (grouted but incompletely hardened, so low resistivity - less than $30{\Omega}m$), (2) weak zone (100-200${\Omega}m$), and (3) hard zone (high resistivity - more than 1000${\Omega}m$) very well for the distance of 320 meters. The 2-D inversion neglects slight absolute 3-D effect, but we can get satisfactory and useful information. Acquired resistivity section and video tapes by borehole camera logging will be reserved and reused if some problem occurs in this site in the future.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.12
• /
• pp.3056-3068
• /
• 1996

This papre presents the RDM algorithm for composition of bit. After this, we propose a digital signature scheme for facsimile document using RDM algorithm. We modify the even-odd feature in distance of changing pel between coding line and multiple reference line which have been scanned before, and run-length in coding line. The time to take in signature is reduced by spreading of signature. Non-repudiation in origin, the 3rd condition of digital signature is realized by proposed digital signature scheme. The transmitter embeds the signature secretly and tensfers it, and the receiver makes a check of any forgery on the signature and the document. This scheme is compatible with the ITU-T.4(G3 or G4 facsimile standard). The total amount of data transmitted and the quality of image are about the same to that of the original document, thus a third party does not notics signature embeded on the document.