• Journal of Positioning, Navigation, and Timing
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• v.13 no.3
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• pp.257-268
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• 2024

The Korea Augmentation Satellite System (KASS) satellite was successfully launched and service is being started. By receiving messages transmitted from the KASS satellite, users can employ the messages to improve positioning accuracy or to verify the integrity of Global Positioning System (GPS). In this paper, we propose a test method for a beam-formed GPS receiver developed to improve the survivability of KASS augmented messages that can enhance positioning accuracy even in an environment with jamming or interfering signals. Through the test method proposed in this paper, quantitative verification is performed for a beam-formed GPS receiver aimed at maintaining the augmented navigation solution to which KASS augmented messages are applied by tracking the KASS signal as much as possible under conditions where the jamming signal strength is gradually increasing. In addition, the proposed test method includes three conditions; first, a static lab test method for repeated verification of functions under the same conditions; second, a static outdoor test method for performance verification in an operating environment of a platform equipped with the beam-formed GPS receiver; and finally, a dynamic lab test method for performance verification of a moving platform equipped with the beam-formed GPS receiver toward a jammer. In this paper, we propose a method for simulating the jamming signal incident direction through the phase delay of an RF cable designed to prevent unintentional jamming signal emission in both lab and outdoor tests, and a method of applying test software for injecting a jamming signal to compare the survivability performance consistently according to the presence or absence of beamforming signal processing. Through the proposed test method, it was verified that the augmented navigation solution could be output for a longer time period when the beamforming signal processing was applied to the KASS satellite signal in the beam-formed GPS receiver.

• Korean Journal of Cognitive Science
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• v.25 no.3
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• pp.211-232
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• 2014

People search a certain object or a person so many time in a day. Besides the information about what the target is, perceptual information of the target can influence on the search process. In the current study, using an eye-tracker we aimed to examine whether the perceptual information of previewing target stimuli on the visual search process of the target and the task performance. Participants had to identify the previewing target stimulus presented in the middle of the screen, and then had to search the target among 8 items presented in a circle array, and had to decide whether the size of the target in the search display was same as that of the previewing stimulus. The experimental conditions were divided into 8 within-subject conditions by whether the search display was consisted of all the same size items or different size items (homogeneous search display vs. inhomogeneous search display), by the size of the preview target stimulus, and by the size of the target stimulus in the search display. Research hypothesis is that the size information of the previewing influence on the visual search process of the target and task performance when the items in the search display are in different sizes. In the results of behavioral data analysis, the reaction time showed the main effect of the search display, and the size of the target stimulus in the search display. and the interaction between the size consistency effect of target stimulus and the search display condition. In the results of analysis of eye-movement information, the Initial Saccade to Target Ratio measurement showed the interaction between the size consistency effect of target stimulus and the search display condition as the reaction time measurement did. That is, the size consistency effect of target stimulus only in the inhomogeneous search display condition indicated that participants searched the items in the same size as that of preview target stimulus. Post-hoc analyses revealed that the search and task performance in the inhomogeneous display condition were faster when the target size was consistent, but rather slower when the target size was inconsistent.

• Journal of Global Scholars of Marketing Science
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• v.20 no.2
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• pp.173-178
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• 2010

A privately held, third generation family owned company, Boom Technologies, Inc. (BTI), a provider of products and services to the electric utility, telecommunications and contractor markets, continues to make progress in exporting. Although export sales only equaled 5% of total revenue in 2008, BTI has an entire export division. Their export division's Managing Director reveals the trial and errors of a privately held company and their quest for success overseas. From its inception, BTI has always believed its greatest asset is its employees. When export sales struggled due to lack of strategy and direction, BTI hired a Managing Director for its export division. With leadership and guidance from BTI's president and from the Managing Director, they utilized the department's skills and knowledge. Structural changes were made to expand their market presence abroad and increase export sales. As a result, export sales increased four-fold, area managers in new countries were added and distribution networks were successfully cultivated. At times, revenue generation was difficult to determine due to the structure of the company. Therefore, in 1996, the export division was restructured as a limited liability company. This allowed the company to improve the tracking of revenue and expenses. Originally, 80% of BTI's export sales came from two countries; therefore, the initial approach to selling overseas was not reaching their anticipated goals of expanding their foreign market presence. However, changes were made and now the company manages the details of selling to over 80 countries. There were three major export expansion challenges noted by the Managing Director: 1. Product and Shipping - The major obstacle for BTI was product assembly. Originally, the majority of the product was assembled in the United States, which increased shipping and packaging costs. With so many parts specified in the order, many times the order would arrive with parts missing. The missing parts could equate to tens of thousands of dollars. Shipping these missing parts separately in another shipment also cost tens of thousands of dollar, plus a delivery delay time of six to eight weeks; all of which came out of the BTI's pockets. 2. Product Adaptation - Safety and product standards varied widely for each of the 80 countries to which BTI exported. Weights, special licenses, product specification requirements, measurement systems, and truck stability can all differ from country to country and can serve as a type of barrier to entry, making it difficult to adapt products accordingly. Technical and safety standards are barriers that serve as a type of protection for the local industry and can stand in the way of successfully pursuing foreign markets. 3. Marketing Challenges - The importance of distribution creates many challenges for BTI as they attempt to determine how each country prefers to operate with regard to their distribution systems. Some countries have competition from a small competitor that only produces one competing product; whereas BTI manufactures over 100 products. Marketing material is another concern for BTI as they attempt to push marketing costs to the distributors. Adapting the marketing material can be costly in terms of translation and cultural differences. In addition, the size of paper in the United States differs from those in some countries, causing many problems when attempting to copy the same layout and With distribution being one of several challenges for BTI, the company claims their distribution network is one of their competitive advantages, as the location and names of their distributors are not revealed. In addition, BTI rotates two offerings yearly: training to their distributors one year and then the next is a distributor's meeting. With a focus on product and shipping, product adaptation, and marketing challenges, the intricacies of selling overseas takes time and patience. Another competitive advantage noted is BTI's cradle to grave strategy, where they follow the product from sale to its final resting place, whether the truck is leased or purchased new or used. They also offer service and maintenance plans with a detailed cost analysis provided to the company prior to purchasing or leasing the product. Expanding abroad will always create challenges for a company. As the Managing Director stated, "If you don't have patience (in the export business), you better do something else." Knowing how to adapt quickly provides BTI with the skills necessary to adjust to the changing needs of each country and its own unique challenges, allowing them to remain competitive.

• Progress in Medical Physics
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• v.20 no.3
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• pp.132-138
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• 2009

Studies on target motion in 4-dimensional radiotherapy are being world-widely conducted to enhance treatment record and protection of normal organs. Prediction of tumor motion might be very useful and/or essential for especially free-breathing system during radiation delivery such as respiratory gating system and tumor tracking system. Neural network is powerful to express a time series with nonlinearity because its prediction algorithm is not governed by statistic formula but finds a rule of data expression. This study intended to assess applicability of neural network method to predict tumor motion in 4-dimensional radiotherapy. Scaled Conjugate Gradient algorithm was employed as a learning algorithm. Considering reparation data for 10 patients, prediction by the neural network algorithms was compared with the measurement by the real-time position management (RPM) system. The results showed that the neural network algorithm has the excellent accuracy of maximum absolute error smaller than 3 mm, except for the cases in which the maximum amplitude of respiration is over the range of respiration used in the learning process of neural network. It indicates the insufficient learning of the neural network for extrapolation. The problem could be solved by acquiring a full range of respiration before learning procedure. Further works are programmed to verify a feasibility of practical application for 4-dimensional treatment system, including prediction performance according to various system latency and irregular patterns of respiration.

• Journal of The Korean Association For Science Education
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• v.33 no.4
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• pp.778-793
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• 2013

The purpose of this study is to analyze observation characteristics through eye movement according to cognitive styles. To do this, we developed observation tasks that show the differences between wholistic cognitive style group and analytic cognitive style group, measured eye movement of university students with different cognitive styles after being given an observation task. The difference between two cognitive style groups is confirmed by analysing gathered statistics and visualization data. The findings of this study are as follows: First, to compare fixation time and frequency, we compared the average value of total time used in the observation task by the wholistic cognitive style group and analytic cognitive style group. The numbers of Fixation (total) and number of Fixations (30s), is based on the fact that the wholistic cognitive style group has more numbers of fixation (Total) and number of fixations (30s) means the wholistic cognitive style group can observe more points or overall features than the analytic cognitive style group, in contrast, the analytic cognitive style group tend to focus on a particular detail, and observe less numbers of points. Second, to compare observation object and area by cognitive style, the outcome of analysing visualization data shows that wholistic cognitive style group observes the surrounding environment of spider and web on a wider area, on the other hand, the analytic cognitive style group observes by focusing on the spider itself. Through the result of this study, there are differences in observation time, frequency, object, area, and ratio from the two cognitive styles. It also shows the reason why each student has varied outcome, from the difference of information following their cognitive styles, and the result of this study helps to figure out and give direction as to what observation fulfillment is more suitable for each student.

• Radiation Oncology Journal
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• v.23 no.4
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• pp.217-222
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• 2005

Purpose: To develop the respiration simulating phantom with thermocouple for evaluating 4D radiotherapy such as gated radiotherapy breathing control radiotherapy and dynamic tumor tracking radiotherapy. Materials and Methods: The respiration monitoring mask(ReMM) with thermocouple was developed to monitor the patient's irregular respiration. The signal from ReMM controls the simulating phantom as organ motion of patients in real-time. The organ and the phantom motion were compared with its respiratory curves to evaluate the simulating phantom. ReMM was used to measure patients' respiration, and the movement of simulating phantom was measured by using $RPM^{(R)}$. The fluoroscope was used to monitor the patient's diaphragm motion. relative to the organ motion, respectively. The standard deviation of discrepancy between the respiratory curve and the organ motion was 8.52% of motion range. Conclusion: Patients felt comfortable with ReMM. The relationship between the signal from ReMM and the organ motion shows strong correlation. The phantom simulates the organ motion in real-time according to the respiratory signal from the ReMM. It is expected that the simulating phantom with ReMM could be used to verify the 4D radiotherapy.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.67-75
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• 2018

Purpose The purpose of this study is to investigate and analyze the external dose rates of $^{18}F-FDG$ Whole Body PET/CT patients by distance, and to identify the main factors that contribute to the reduction of radiation dose by checking the cumulative doses of nuclear medicine technologist(NMT). Materials and Methods After completion of the $^{18}F-FDG$ Whole Body PET/CT scan($75.4{\pm}3.3min$), the external dose rates of 106 patients were measured at a distance of 0, 10, 30, 50, and 100 cm from the chest. Gender, age, BMI(Body Mass Index), fasting time, diabetes mellitus, radiopharmaceutical injection information, creatine value were collected to analyze individual factors that could affect external dose rates from a patient's perspective. From the perspective of NMT, personal pocket dosimeters were worn on the chest to record accumulated dose of NMT who performed the injection task($T_1$, $T_2$ and $T_3$) and scan task($T_4$, $T_5$ and $T_6$). In addition, patient contact time with NMT was measured and analyzed. Results External dose rates from the patient for each distance were calculated as $246.9{\pm}37.6$, $129.9{\pm}16.7$, $61.2{\pm}9.1$, $34.4{\pm}5.9$, and $13.1{\pm}2.4{\mu}Sv/hr$ respectively. On the patient's aspect, there was a significant difference in the proximity of gender, BMI, Injection dose and creatine value, but the difference decreased as the distance increased. In case of dialysis patient, external dose rates for each distance were exceptionally higher than other patients. On the NMT aspect, the doses received from patients were 0.70, 1.09, $0.55{\mu}Sv/person$ for performing the injection task($T_1$, $T_2$, and $T_3$), and were 1.25, 0.82, $1.23{\mu}Sv/person$ for performing the scan task($T_4$, $T_5$, $T_6$). Conclusion we found that maintaining proper distance with patient and reducing contact time with patient had a significant effect on accumulated doses. Considering those points, efforts such as sufficient water intake and encourage of urination, maintaining the proper distance between the NMT and the patient(at least 100 cm), and reducing the contact time should be done for reducing dose rates not only patient but also NMT.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.1
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• pp.95-107
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• 2017

In this study, a preliminary study was undertaken for development of a tunnel incident automatic detection system based on a machine learning algorithm which is to detect a number of incidents taking place in tunnel in real time and also to be able to identify the type of incident. Two road sites where CCTVs are operating have been selected and a part of CCTV images are treated to produce sets of training data. The data sets are composed of position and time information of moving objects on CCTV screen which are extracted by initially detecting and tracking of incoming objects into CCTV screen by using a conventional image processing technique available in this study. And the data sets are matched with 6 categories of events such as lane change, stoping, etc which are also involved in the training data sets. The training data are learnt by a resilience neural network where two hidden layers are applied and 9 architectural models are set up for parametric studies, from which the architectural model, 300(first hidden layer)-150(second hidden layer) is found to be optimum in highest accuracy with respect to training data as well as testing data not used for training. From this study, it was shown that the highly variable and complex traffic and incident features could be well identified without any definition of feature regulation by using a concept of machine learning. In addition, detection capability and accuracy of the machine learning based system will be automatically enhanced as much as big data of CCTV images in tunnel becomes rich.

• Environmental Mutagens and Carcinogens
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• v.24 no.1
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• pp.15-18
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• 2004

There are significant differences in the extent of drug interactions between subjects. The influence of the genetic make up of drug metabolizing enzyme activities (CYP3A5, CYP2C19 and UDP-glucuronosyl transferase) on the pharmacokinetic drug interaction potential were studied in vivo. Nineteen healthy volunteers were grouped with regard to the $CYP3A5^{*}3$ allele, into homozygous wild-type (CYP3A5^{*}1/1^{*}1$, n=6), heterozygous $(CYP3A5^{*}1/^{*}3$, n=6), and homozygous variant-type $(CYP3A5^{*}3/^{*}3$, n=7) subject groups. The pharmacokinetic profile of intravenous midazolam was characterized before and after itraconazole administration (200 mg once daily for 4 days), and also following rifampin pretreatment (600 mg once daily for 10 days), with a washout period of 2 weeks in between. For omeprazole and moclobemide pharmacokinetic interaction study 16 healthy volunteers were recruited. The volunteer group comprised 8 extensive metabolizers and 8 poor metabolizers of CYP2C19, which was confirmed by genotyping. Subjects were randomly allocated into two sequence groups, and a single-blind, placebo-controlled, two-period crossover study was performed. In study I, a placebo was orally administered for 7 days. On the eighth morning, 300 mg of moclobemide and 40 mg of placebo were coadministered with 200 mL of water, and a pharmacokinetic study was performed. During study n, 40 mg of omeprazole was given each morning instead of placebo, and pharmacokinetic studies were performed on the first and eighth day with 300 mg of moclobemide coadministration. In the UGT study pharmacokinetics and dynamics of 2 mg intravenous lorazepam were evaluated before and after rifampin pretreatment (600 mg once daily for 10 days), with a washout period of 2 weeks in between. The subjective and objective pharmacodynamic tests were done before and 1, 2, 4, 6, 8, and 12 hrs after lorazepam administration. The pharmacokinetic profiles of midazolam and of its hydroxy metabolites did not show differences between the genotype groups under basal and induced metabolic conditions. However, during the inhibited metabolic state, the $CYP3A5^{*}3/^{*}3$ group showed a greater decrease in systemic clearance than the $CYP3A5^{*}1/^{*}1$ group $(8.5\pm3.8$ L/h/70 kg vs. $13.5\pm2.7$ L/h/70 kg, P=0.027). The 1'-hydroxymidazolam to midazolam AUC ratio was also significantly lower in the $CYP3A5^{*}3/^{*}3$,/TEX> group $(0.58\pm0.35,$ vs. $1.09\pm0.37$ for the homozygous wild-type group, P=0.026). The inhibition of moclo-bemide metabolism was significant in extensive metabolizers even after a single dose of omeprazole. After daily administration of omeprazole for 1 week, the pharmacokinetic parameters of moclobemide and its metabolites in extensive metabolizers changed to values similar to those in poor metabolizers. In poor meta-bolizers, no remarkable changes in the pharmacokinetic parameters were observed. The area under the time-effect curves of visual analog scale(VAS), choice reaction time, and continuous line tracking test results of lorazepam was reduced by 20%, 7%, 23% respectively in induced state, and in spite of large interindividual variablity, significant statistical difference was shown in VAS(repeated measures ANOVA, p=0.0027).

• Cartoon and Animation Studies
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• s.47
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• pp.1-29
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• 2017

360-degree virtual reality has been a technology that has been available for a long time and has been actively promoted worldwide in recent years due to development of devices such as HMD (Head Mounted Display) and development of hardware for controlling and executing images of virtual reality. The production of the 360 degree VR requires a different mode of production than the traditional video production, and the matters to be considered for the user have begun to appear. Since the virtual reality image is aimed at a platform that requires enthusiasm, presence and interaction, it is necessary to have a suitable cinematography. In VR, users can freely enjoy the world created by the director and have the advantage of being able to concentrate on his interests during playing the image. However, the director had to develope and install the device what the observer could concentrate on the narrative progression and images to be delivered. Among the various methods of transmitting images, the director can use the composition of the short. In this paper, we will study how to effectively apply the technique of directing through the composition of this shot to 360 degrees virtual reality. Currently, there are no killer contents that are still dominant in the world, including inside and outside the country. In this situation, the potential of virtual reality is recognized and various images are produced. So the way of production follows the traditional image production method, and the shot composition is the same. However, in the 360 degree virtual reality, the use of the long take or blocking technique of the conventional third person view point is used as the main production configuration, and the limit of the short configuration is felt. In addition, while the viewer can interactively view the 360-degree screen using the HMD tracking, the configuration of the shot and the connection of the shot are absolutely dependent on the director like the existing cinematography. In this study, I tried to study whether the viewer can freely change the cinematography such as the composition of the shot at a user's desired time using the feature of interaction of the VR image. To do this, 3D animation was created using a game tool called Unreal Engine to construct an interactive image. Using visual scripting of Unreal Engine called blueprint, we create a device that distinguishes the true and false condition of a condition with a trigger node, which makes a variety of shorts. Through this, various direction techniques are developed and related research is expected, and it is expected to help the development of 360 degree VR image.