• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.85-94
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• 2010

Many RFID systems use dynamic slotted ALOHA to identify the label information of the RFID tags. One of the key problems in the RFID system is how to estimate the number of RFID tags up to the desired level of accuracy. In this paper, we present the framework of tag estimation algorithm for the collision-oblivious (CO) reader which can only decide whether the tag response is successful or not. Thus, the CO reader must rely on the success estimator to predict the RFID tag population. We propose two estimation algorithms to predict the number of RFID tags, named the memoryless success estimator (MSE) and the intersection-based success estimator (ISE). The MSE considers only the estimate obtained at the current inventory round, while the ISE finds an appropriate intersection interval of the existing estimates collected at every inventory round. Through the simulation results, we demonstrate that the ISE is a fast, accurate, and controllable estimator whose performance is close to that of the collision/idle estimators.

• Bulletin of the Society of Naval Architects of Korea
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• v.2 no.1
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• pp.9-14
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• 1965

Ship designers make every efforts to get faster ships in accordance with the development of the Naval Architecture. But for the speed lying over factor length ratio 2.5-3.0, we could put a powerful engine into the conventional round bottom displacement type vessels, but it is very difficult in view point of economy, weight and volume. The principal cause of these speed obstacles is the wave making resistance and researchers are trying to decrease this resistance. One of the resolving ways, planing hulls were applied to small high boats. Planing hull's advantage is not restricted to speed, but the workmanship of the planing hull is easier than those of displacement type vessels of round bottom. Planing hull, therefore, are widely applicable to the intermediate speed boats, which don't have enough high speed to take planing advantage, as well as high speed boats. We will discuss related phenomena of the planing hull in details and this paper we particularly interested in the interjection point(speed length ratio 3.0-3.5 by Mr. D. De Groots) between semi-planing and full planing hulls on the resistance characteristic curve. The paper by Prof. Keuck Chun Kim, "Some Characteristics of Straight Framed V-bottom Hull Forms", Journal of the society of Naval Architects of Korea, Vol.1, No.1, Dec.5, 1964, is referred to the V-bottom hull forms belonging to low speed region and determines practical applicable limit of the speed length ratio combined with construction costs, under which are still used by large commercial vessels. This is the interesting contrast between his and authors. We will further discuss the speed length ratio which is considered as a beginning point to planing effect. For this analysis, we choose 3 model ships: Model (1) and (2) have the same principal dimensions, model 3 varied dimension. Model (1) is full-planing hull, (2) is semi-planing hull and (3) is complete planing hull. They are aimed to collect proper design data for purposed ships.

• The Journal of Korean Association of Computer Education
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• v.9 no.2
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• pp.111-124
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• 2006

Multicast services are provided on the Internet in fast increasing. Therefore it is important to keep security for multicast communication. If a member of the group is removed, new group key has to be generated and distributed to all remaining members of group. Minimizing number of messages and operation cost for generation of the composite keys to be used to encrypting group key are important evaluating criteria of multicast key management scheme since generation and distribution of new keys for rekeying require expensive operation. Periodic batch rekeying can reduce these important parameters rather than rekeying sequentially in fashion one after another. In this paper, Hamming distance is calculated between every members to be removed. In batch rekeying the members with Hamming distance less than threshold are selected for rekeying procedure. With running the round assignment algorithm in the case of removing several members simultaneously, our scheme has advantages of reducing messages and operation cost for generation of the composite keys and eliminating possibility of collusion attack for rekeying. We evaluate performance of round assignment algorithm through simulation and show that our scheme is excellent after performance comparison of existent schemes and our scheme.

• Explosives and Blasting
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• v.24 no.2
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• pp.1-8
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• 2006

In this study, a charging density has been differently applied to all holes to improve an excavated length per round on excavating a tunnel in quartzite mine and to prevent a dead pressure phenomena and sintering phenomena. A composition initiating system using simultaneously a direct initiating system and a indirect initiating system with 2 detonators in one hole has been introduced to cut holes. As a bottom part which is difficult to make a free face are charged with a higher charging density and a column part are charged with a lower charging density, the composition charging and initiating system which the power of explosives works effectively in the rock mass is developed. As the results, a dead pressure phenomena and a sintering phenomena being often produced in a hard rock or in a long hole could be prevented. Besides, the workability was improved by about 15% and the specific charge was reduced to about 20%, as an excavated length vs. a drilled length per round could be increased over 95%.

• Korean Journal of Community Nutrition
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• v.9 no.2
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• pp.225-232
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• 2004

The objective of this study is to investigate how patients satisfaction are affected by satisfaction with the patient menu and differentiated service resulting from QI activities and to evaluate the efficiency of QI activities. In order to improve satisfaction with menus through QI activities, this study strengthened meal round, examined the quantity of food waste produced by patients, diversified one-dish menus and used seasonal food as much as possible to reflect patients ′tastes to the maximum. With regard to cooking, additionally, it strengthened sampling and standardized recipes to maintain the constancy of taste and cooking/seasoning. From July 2003, dining time was changed from 08 : 00 to 07 : 30 for breakfast and from 17 : 30 to 18 : 00 for dinner. Statistical data analyses were completed using the SPSS 11.0 program. The results can be summarized as follows: The goal of QI was to improve food service by raising the score of "Satisfaction with Offered Menus" from 3.49 before QI to 3.55 after QI and differentiating nutrition service at the VIP ward. The score of "Satisfaction with offered menus" after QI was 3.56, and services related to the VIP ward were 7 dishes per meal, meal round once per day and the use of a napkin for a spoon in setting the table. In addition a variety of dishes were used in order to heighten the visual effect. Among the 10 items included on the patient satisfaction questionnaire, 8 items showed higher scores before QI. "Taste of meals" (p ＜ 0.05), "Satisfaction with offered menus" (p ＜ 0.05), "Kindness of meal serving assistants" (p ＜ 0.05) and "Cleanliness of clothes ＆ features" (p ＜0.05) of VIP ward were significantly higher than those of a general ward.

• Journal of the Institute of Convergence Signal Processing
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• v.1 no.2
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• pp.177-185
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• 2000

In this paper CPLD design of cryptographic coprocessor which implements SEED algorithm is described. To satisfy trade-off between area and speed, the coprocessor has structure in which 1 round operation is divided into three subrounds and then each subround is executed using one clock. To improve clock frequency, online precomputation scheme for round key is used. To apply the coprocessor to various applications, four operating modes such as ECB, CBC, CFB, and OFB are supported. The cryptographic coprocessor is designed using Altera EPF10K100GC503-3 CPLD device and its operation is verified by encryption or decryption of text files through ISA bus interface. It consists of about 29,300 gates and performance of CPLD chip is about 44 Mbps encryption or decryption rate under 18 Mhz clock frequency and ECB mode.

• Research in Plant Disease
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• v.11 no.1
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• pp.48-55
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• 2005

Cylindrocarpon destructans is a soil-borne plant pathogenic fungus causing root rot on ginseng and trees. Rapid and exact detection of this pathogen was practiced on ginseng seedlings by nested PCR using speciesspecific primer set. The second round of PCR amplification by Dest 1 and Dest 4 primer set formed 400 bp of species-specific fragment of C. destructans from the product of first round of amplification by ITS 1 and ITS 4 primer set. In the PCR sensitivity test based on DNA density, nested PCR detected to the limit of one fg and it meant the nested PCR could detect up to a few spores of C. destructans. Also, nested PCR made it possible to detect the pathogen from ginseng seedlings infected by replantation on artificial infested soil. Our nested PCR results using species-specific primer set could be utilized for diagnosis of root rot disease in ginseng cultivation.

• Archives of Plastic Surgery
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• v.34 no.1
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• pp.119-122
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• 2007

Purpose: Although liposarcoma is the second most common soft tissue sarcoma in adults, the incidence of liposarcoma of the head and neck is rare. There is only one reported case in Korea and moreover, only in adolescence. We report a case of liposarcoma on the neck in a 32-year-old male in adult. Methods: The patient had a slow growing, none tender mass on the posterior neck without lymphadenopathy, which has been present for 3 years and recurred twice during that time. MRI showed a 1.5 cm sized ovoid, well demarcated mass that was located in the subcutaneous layer of the posterior neck. Results: The mass was surgically removed. The resection margin was free of tumor on frozen biopsy and histopathologic examination indicated myxoid and round cell liposarcoma. The whole body F-18 FDG PET-CT applied on the fourteenth day postoperatively, revealed a moderate FDG-uptaking soft tissue lesion showing postoperative wound healing process on the posterior neck region and there was no distant metastasis. Conclusion: Liposarcoma is the second most common soft tissue sarcoma in adults. But, it rarely involves the head and neck region. Prognosis is principally dependent on histologic subtype and grade. Low grade liposarcoma such as well differentiated and myxoid liposarcoma tend to recur locally, rarely metastasize. On the other hand, high grade liposarcoma such as round cell and pleomorphic liposarcoma have higher rates of local recurrence and distant metastasis. Complete surgical excision provides the most effective means of treatment. Radiotherapy or chemotherapy can be used as an asjunctive treatment modality.

• Korean Journal of Heritage: History & Science
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• v.39
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• pp.281-314
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• 2006

Several explanations exist about the usage of disk-shaped bronze implements in the ancient society. Some argue that they were used as mirrors, others suggest percussion instruments, and still others bronze ornaments. Differences between disk-shaped bronze implements and mirrors with multiple knobs are that the former have no visible design, only one handle, and a sharp curvature unlike the latter with smooth curvature. The question is whether disk-shaped bronze implements excavated from Korean peninsula have any light reflecting function. To answer this question, I carefully studied the concave surfaces of disk-shaped bronze implements excavated from Goejeong-dong, Tongso-ri and Hapsong-ri sites. The main findings are as follows: (1) The concave sides of the disk-shaped bronze implements excavated from Goejeong-dong and Tongso-ri sites were highly polished, and they were as reflective as bronze mirrors. (2) The concave side of the disk-shaped bronze implement from Hapsong-ri site was unpolished, and it was different from bronze mirrors. (3) As for the convex sides of the disk-shaped bronze implements, they did not appear to have been polished with care. Considering the above findings, the disk-shaped bronze implements excavated from Goejeong-dong and Tongso-ri sites belong to the stage where they could act as both mirrors and instruments. On the contrary, the disk-shaped bronze implement from Hapsong-ri site can belong to the stage where it lost the function of being a mirror as the result of maintaining only its function as an instrument. Even though disk-shaped implements had two functions, it can be considered that the light reflecting function expanded the role of a mirror with multiple knobs and the sound function helped the engraved round bronze implement to be converted into an eight-armed bronze rattle. Since it has been reported that shamans used bronze mirrors as percussion instruments in their performances in Korean peninsula and Siberia, I propose a reconsideration of the usage of mirrors in the ancient East Asia. Although the essential function of a mirror is to reflect light, other possible usages involving important functions need to be further investigated.

• Journal of the Korea Fashion and Costume Design Association
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• v.23 no.1
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• pp.47-59
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• 2021

This study aims to provide inspiration and methods for menswear design by analyzing elements for men's fashion using flower images. The results are as follows: Men's fashion types with flower images were categorized as classic tailored, casual tailored, casual wear, sports-outdoor. The order of frquency was casual tailored, casual, classic tailored, and sports outdoor. For the classic tailored type, the flower images are related with an X-line silhouette, and the arrangement methods, such as a scattered patterns, one-point patterns, and surface techniques, such as printing and embroidery were used, and similar color or monochromatic schemes appeared sequentially. For the casual tailored type, the flower images are related to an H-line silhouette, arrangement methods such as a scattered pattern, panel pattern, and surface techniques, such as print, embroidery, and jacquard were used, similar color and accent color schemes appeared sequentially. For the casual type, the flower images are related to H-line and Y-line silhouettes, and arrangement methods, such as a scattered pattern, all-round continuous pattern, and panel pattern, and surface techniques, such as print, jacquard, embroidery, and patchwork were used, similar color and contrast color schemes appeared sequentially. For the sports outdoor type, the flower image were related to A-line and H-line silhouettes, arrangement methods, such as a scattered pattern and all-round continuous pattern, and surface techniques, such as print and jacquard were used, monochromatic scheme and contrast color schemes appeared sequentially. Therefore, the flower images in men's fashion were applied to various design elements, and displayed an interesting result, different from conventional design approach.