• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.4
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• pp.447-455
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• 2018

If a hidden enemy is shooting, there is a threat against soldiers in recent conflicts. This paper aims to improve the localization of a muzzle using microphone array. Gunshot noise can provide information about the location of muzzle with two signals, the muzzle blast from the gun barrel and the projectile sound from the bullet. Two signals arrive to the microphone array with different arrival time and angle. If the arrival angles of the two signals are estimated, distance between sniper location and the microphone array can be calculated by using geometric principles. This method was established in 2003 by Pare. But this method has a limitation that it cannot calculate the distance when the arrival angles of the two signals are same. Also it has an error when the angle difference of arrival is small. In order to overcome this limitation, a new method is proposed that uses the change of characteristic of the projectile sound with respect to vertical distance from the trajectory. The proposed method estimates the distance correctly when the arrival angle of two signals are same, and when the angle difference between two signals is increased, the estimation error increases with respect to the angle. Therefore these two methods can be selected according to the angle difference between two signals to estimate the distance of the muzzle. Below the threshold of the angle difference, the proposed method can be used to estimate distance with smaller error than the existing method. This was demonstrated by shooting tests using actual sniper rifles.

• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.149-157
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• 2011

Passive tags are inferior to active tags in processing efficiency, so they have difficulty in largevolume processing. The proposed protocol reduces the volume of computation in passive tags and, at the same time, improves authentication for enhanced safety and security. That is, different from existing RFID protocols that return the same value even if an error happens when the reader reads a tag, the improved RFID security protocol returns a new value using a re-counter and processes the computation part of a tag in the reader or in a back.end system. Even if the information of a tag is acquired by an malicious way, it is not actual information but encrypted information that is not usable. In addition, even if tag information is read in sequence, it is changed in each read, so the protocol is safe from Location Tracking.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2172-2178
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• 2007

In indoor environment, the combination of the two variations, large scale(path loss) and small scale(fading), leads to non-linear variation of RSSI(received signal strength indicator) values as distance varied. This has been one of the difficulties for indoor location estimation. This paper presents new findings on indoor RSSI characterization for more accurate model building. Experiments have been done statistically to find overall trend of RSSI values at different places and times within the same room. From experiments, it has been shown that the variation of RSSI values can be determined by both spatial and temporal factors. These two factors are directly indicated by the two main parameters of path loss model. The results show that all sensor nodes which are located at different places share the same characterization value for the temporal parameter whereas different values for the spatial parameters. The temporal parameter also has a large scale variation effect that is slowly time varying due to environmental changes. Using this relationship, the characterization for location estimation can be more efficient and accurate.

• The Journal of the Acoustical Society of Korea
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• v.41 no.4
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• pp.389-396
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• 2022

This paper aims to identify the causes and mechanisms of contraction-expansion noise in refrigerators and proposes noise reduction methods. Contraction-expansion noise generated in refrigerators is mainly due to stick-slip phenomenon occurring on the contact surface between inner parts. Friction experiments were conducted to identify the factors causing the stick-slip phenomenon. Furthermore, the vibration level of the internal components was measured to determine the characteristics and location of the contraction-expansion noise. Based on the experimental results, experiments have been conducted to verify the noise characteristics for each factor. From this, it was confirmed that the friction experiment and the refrigerator contraction-expansion noise generation location and frequency were the same. The vibration level also increased as the vertical force was increased due to load loading. Also, it was confirmed that the contraction-expansion noise was reduced when the surface roughness was increased. Therefore, it was concluded that increasing the surface roughness of the contact surface in the same way as the results of the friction experiment was the method of reducing contraction-expansion noise.

• The Korea Journal of Herbology
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• v.34 no.1
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• pp.33-42
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• 2019

Objectives : This study aimed to be used as basic data for obtaining excellent quality of Salvia miltiorrhiza (SM) root. Methods : SM cultivated in Anhui Bozou, Henan, Shandong, Henan Wenxian, Zhejiang, Hebei, Liaoning, Shanxi, Shaanxi Shangluo, Sichuan Zhongjiang, Sichuan Minyang and Jiangsu in China were gathered and its internal morphology and physicochemical patterns were analyzed. Results : Cross-section of sang plants according to cultivated regions in China showed that cork layers consisted of cells with four to six layers, cortex width was wide, and phloem was semilunar-shaped. Although there are forms layers, yet boundary was vague. It was observed that eight to ten vascular bundles were arranged in wooden parts in all directions and as a single line of vascular was distributed nearby form layers as it nears to the center. Tanshinon IIA identified a spot in the same location with standard product near by Rf 0.9 in the test identifying TLC of SM according to cultivated areas in China. The largest amount was 0.535% identified in Shandong and the lowest amount of 0.05% in Hebei. Salvianolic acid B identified a spot in the same location with standard product near by Rf 0.7 in the test identifying TLC of SM according to cultivated areas in China. The largest amount was 2.72% identified in Liaoning and the lowest amount of 0.825% in Jiangsu. Conclusions : The results are assumed to be used as basic data for obtaining excellent quality of SM oriental medical hers and distinguishing authentic or fake herbs.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.835-843
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• 2023

Given the structure of XML data, path and tree pattern matching algorithms play an important role in XML query processing. To facilitate decisions or relationships between nodes, nodes in an XML tree are typically labeled in a way that can quickly establish an ancestor-descendant on relationship between two nodes. However, these techniques have the disadvantage of re-labeling existing nodes or recalculating certain values if insertion occurs due to sequential updates. Therefore, in current labeling techniques, the cost of updating labels is very high. In this paper, we propose a new labeling technique called Fast XML encoding, which supports the update of order-sensitive XML documents without re-labeling or recalculation. It also controls the length of the label by reusing deleted labels at the same location in the XML tree. The proposed reuse algorithm can reduce the length of the label when all deleted labels are inserted in the same location. The proposed technique in the experimental results can efficiently handle order-sensitive queries and updates.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.1
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• pp.141-151
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• 2014

Social enterprises provide the job and social service to the weak classes at the same time. As the weak classes such as the aged and disabled who are the main consumers of social enterprises are restricted in moving and gradual approach, so social service providers are required to decide the location by considering their gradual approach more than anythingelse. Therefore, in case of deciding the location of social enterprises it is more important than anythingelse for the social enterprises to select the location by considering the demand of social service of the region preferentially unlike the principles of deciding the location of ordinary enterprises. However, it has been expected that the main causes of various supplying and consuming sides which are provided not only to the ordinary but also the social enterprises might be distributed indiscriminately and unequally in the space of national land by diverse main causes such as the kinds of the products, concentration of the consuming sides, manpower distribution and others, and in this study, what have been used for the examination of regional distribution characteristics of social enterprises which have been operated by being distributed regionally were LQ technique, and the regional distribution characteristics of social enterprises of Korea have been suggested after having them analyzed. This study has the aim of providing the suggestions for the establishment of the policies for the promotion of social enterprises in the future by clarifying the present situations and characteristics of regional distribution of social enterprises of Korea which have been functioning as the suppliers of private social service, and what are required at this time are the political support and social agreement for the location and growth through continuous studies.

• Korean Journal of Head & Neck Oncology
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• v.22 no.1
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• pp.29-32
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• 2006

Background: The location of parotid gland tumors can influence the duration and the difficulty of the operation. If the information about tumor location was available preoperatively, it would allow accurate operative planning and counseling of patients in terms of the length of the operation and the potential morbidity. Methods: This study was based on a retrospective review of 100 patients with parotid gland tumors underwent parotidectomy from January 2000 to October 2005 at Yong-Dong Severance Hospital. Based on computed tomographic(CT) scan findings, 4 landmarks such as facial nerve(FN) line, Utrecht(U) line, Conn's are(CA), and retromandibular vein (RV) were drawn on the scans in same plane. The location of tumors were determined by the landmarks and confirmed by the operative findings. The accuracy of each landmarks was evaluated. To find out the accuracies according to tumor size, the tumors were divided into 2 groups; less than 2 cm and larger than 2 cm in diameter. Results: U line was the most accurate(94%), sensitive(89.3%) and specific(97.7%) in predicting tumor location of the parotid gland. However, in small tumors less than 2cm, FN line (p=0.022) and RV criteria (p=0.028) were more reliable in accuracy. Conclusion: CA, FN line, U line, and RV are all useful landmarks in preoperative prediction for the location of parotid gland tumors. However, U line was the most accurate, but we must consider that proper landmark should be used in prediction according to the size of tumor because the accuracy of landmark may change.

• Korean Journal of Acupuncture
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• v.17 no.1
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• pp.157-171
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• 2000

Front Points are told to be deeply related with viscera and bowels in oriental medicine. Since the Front Points are treated as response zone, it can be used for the diagnosis and treatment of disease in viscera and bowels. The location of Front Points are very similar to the several response zones in western medicine. Diagnostic aspect of Front Points to several response zones were discussed in here based on many thesis and reported laboratorial experiments. Front Points are located in the same latitude of viscera and bowels. So, diagnosis result in Front Points represent condition of each organs. Palpitation of the Front Points can make diagnosis of body surface and the organ beneath the body surface. Such use of Front Points for diagnosis can used as the treatment points also. Only three Front Points (LU-1, LI-14, GB-24) in lung, liver and gall bladder meridian are located on its meridian. The Front Points of Stomach (CV-12) cross its meridian or closely located to it. Unlike to those four Front Points that are matched to its meridian, other eight Front Points do not located or cross its meridian at all. It seems that the location of Front Points are decided by the location of organs and the conditions at a certain organ do not delivered by the meridians but delivered by main collaterals, tertiary collaterals and superficial collaterals instead. Among visceral response zones, Five Front Points (CV-3, CV-4, CV-12, LI-14, GB-25) are exactly matched to Head's response zone and other Front Points are closely matched to the Head's response zone. There are five Front Points (CV-12, CV-14, CV-17, LI-14, GB-24) that are matched with the location of pressing palpitation point and other Front Points are closely located to the pressing palpitation point. So far, it was clear that the Front Points do have important role as response points. Symptoms expressed to the Front Points were delivered conditions or symptoms occur in corresponding organ and the anatomical location of Front Points were also found near the corresponding organ. Diagnostic and therapeutic application of Front Points for Organ theory and in the Interpromotion-restraint of the five elements in oriental medicine can be made in future to increase its potential.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.422-429
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• 2007

Location awareness is one of the key functionalities to build an U-city. Recently, many of works of the location-aware systems are emerging to commercially apply to on-going large-scale apartment complex based on U-city. As dwellers or cars being attached with active tags are moving in the U-city complex, the active tags periodically broadcast their own identifiers and receivers fixed along the street or in building use those information to calculate location of them. There are several issues to be considered for such an environment. The first is that the number of active tags operating in the same region are large as much as tens of thousands, and the second is that the active tags should be alive without change of batteries more than a year, hence low power consumption is very important. In this paper we propose i) a new architecture for location-aware system considering such issues, ii) technical issues to implement it using active tags, and iii) a mathematical analytic model to investigate overall performance and verify it by comparing with actual experimental results. Through the analysis we can show the theoretical boundary of the lowest packet loss rate and the maximum number of tags with acceptable performance for the systems based on active tags. The results can be applied to practical design of location-based systems of U-City projects.