• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2003년도 추계학술대회 및 정기총회
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• pp.121-124
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• 2003

It is a major concern of e-shopping mall managers to satisfy a variety of customer's desire by recommending a proper commodity to the expected purchaser. Customer information like customer's fondness and idiosyncrasy in shopping has not been used effectively for the customers or the suppliers. Conventionally, e-shopping mall managers have recommended specific items of commodities to their customers without considering thoroughly in a customer point of view. This study introduces the ways of a choosing and recommending of commodities for customer themselves or others. A similarity measure between one member's idiosyncrasy and the other members' is developed based on the rule base and the case base. The case base is improved by recognizing and learning the changes of customer's desire and shopping trend.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제37권
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• pp.39.1-39.6
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• 2015

Skull-base osteomyelitis is a rare disease affecting the medulla of the temporal, sphenoid, and occipital bones. In general, it occurs due to external ear canal infections caused by malignant external otitis. Skull-base osteomyelitis usually affects elderly diabetic patients. The patient, a 58-year-old man, was referred for evaluation and management of the left jaw. Clinical examination of the patient revealed pain in the left jaw and mouth-opening deflection to the left. The maximum active mouth opening was measured to about 27 mm. Panoramic, CT, and CBCT revealed bone resorption patterns in the left condyle. Through control of diabetes, continued pharmacological treatment, arthrocentesis, and occlusal stabilization appliance therapy were carried out. The extent of active mouth opening was increased to 45 mm, and pain in the left jaw joint was alleviated. This was a case wherein complications caused by failure to control diabetes induced skull-base osteomyelitis. There is a need for continued discussion about the advantages and disadvantages of arthrocentesis with lavage for patients with skull-base osteomyelitis and other treatment options.

• 전산구조공학
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• 제9권3호
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• pp.125-134
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• 1996

건물기초를 지진절연하면 건물뿐만 아니라 그 내부구조물의 지진응답도 크게 감소한다는 사실이 많은 연구를 통해 확인되어 왔다. 그런데 이러한 내부구조물이 유체내에 잠기고 부가질량효과가 크게 작용되는 조건에 놓이는 경우 오히려 지진응답이 증가할 수 있다. 본 논문은 건물 내 수중구조물의 지진해석을 통해 그러한 예를 제시하고자 한다. 해석결과 지진절연된 건물의 경우 이러한 내부 수중구조물의 지진응답이 상당히 증가할 수 있기 때문에 이에 대한 조치가 필요함을 보였고, 적절한 설계에 의하여 부가질량효과를 조절함으로써 어느정도 응답을 줄일 수 있다는 사실을 알 수 있었다.

• Smart Structures and Systems
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• 제18권2호
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• pp.293-315
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• 2016

Seismic isolation is often used in protecting mission-critical structures including hospitals, data centers, telecommunication buildings, etc. Such structures typically house vibration-sensitive equipment which has to provide continued service but may fail in case sustained accelerations during earthquakes exceed threshold limit values. Thus, peak floor acceleration is one of the two main parameters that control the design of such structures while the other one is peak base displacement since the overall safety of the structure depends on the safety of the isolation system. And in case peak base displacement exceeds the design base displacement during an earthquake, rupture and/or buckling of isolators as well as bumping against stops around the seismic gap may occur. Therefore, obtaining accurate peak floor accelerations and peak base displacement is vital. However, although nominal design values for isolation system and superstructure parameters are calculated in order to meet target peak design base displacement and peak floor accelerations, their actual values may potentially deviate from these nominal design values. In this study, the sensitivity of the seismic performance of structures equipped with linear and nonlinear seismic isolation systems to the aforementioned potential deviations is assessed in the context of a benchmark shear building under different earthquake records with near-fault and far-fault characteristics. The results put forth the degree of sensitivity of peak top floor acceleration and peak base displacement to superstructure parameters including mass, stiffness, and damping and isolation system parameters including stiffness, damping, yield strength, yield displacement, and post-yield to pre-yield stiffness ratio.

• Structural Monitoring and Maintenance
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• 제10권3호
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• pp.243-260
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• 2023

Indonesia has had seismic codes for earthquake-resistant structures designs since 1970 and has been updated five times to the latest in 2019. In updating the Indonesian seismic codes, seismic hazard maps for design also update, and there are changes to the Peak Ground Acceleration (PGA). Indonesian seismic design uses the concept of building performance levels consisting of Immediate occupancy (IO), Life Safety (LS), and Collapse Prevention (CP). Related to this performance level, cases still found that buildings were damaged more than their performance targets after the earthquake. Based on the above issues, this study aims to analyze the performance of base isolation design on existing target buildings and analyze the seismic fragility for a case study in Indonesia. The target building is a prototype design 8-story medium-rise residential building using the reinforced concrete moment frame structure. Seismic fragility analysis uses Incremental Dynamic Analysis (IDA) with Nonlinear Time History Analysis (NLTHA) and eleven selected ground motions based on soil classification, magnitude, fault distance, and earthquake source mechanism. The comparison result of IDA shows a trend of significant performance improvement, with the same performance level target and risk category, the base isolation structure can be used at 1.46-3.20 times higher PGA than the fixed base structure. Then the fragility analysis results show that the fixed base structure has a safety margin of 30% and a base isolation structure of 62.5% from the PGA design. This result is useful for assessing existing buildings or considering a new building's performance.

• Imaging Science in Dentistry
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• 제45권1호
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• pp.67-72
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• 2015

Arrested pneumatization of the sphenoid sinus is a developmental variant that is not always well recognized and is often confused with other pathologies associated with the skull base. This report describes the case of a patient referred for cone-beam computed tomography (CBCT) imaging for dental implant therapy. CBCT demonstrated a well-defined incidental lesion in the left sphenoid sinus with soft tissue-like density and sclerotic borders with internal curvilinear opacifications. The differential diagnoses included intraosseous lipoma, arrested pneumatization of the sphenoid sinus, chondrosarcoma, chondroid chordoma, and ossifying fibroma. The radiographic diagnosis of arrested pneumatization was based on the location of the lesion, its well-defined nature, the presence of internal opacifications, and lack of expansion. Gray-scale CBCT imaging of the area demonstrated values similar to fatty tissue. This case highlighted the fact that benign developmental variants associated with the skull base share similar radiographic features with more serious pathological entities.

• 대한수학회보
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• 제51권5호
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• pp.1325-1337
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• 2014

In this paper we study the sequences defined by the last and the last non-zero digits of $n^n$ in base b. For the sequence given by the last digits of $n^n$ in base b, we prove its periodicity using different techniques than those used by W. Sierpinski and R. Hampel. In the case of the sequence given by the last non-zero digits of $n^n$ in base b (which had been studied only for b = 10) we show the non-periodicity of the sequence when b is an odd prime power and when it is even and square-free. We also show that if $b=2^2{^s}$ the sequence is periodic and conjecture that this is the only such case.

• The Korean Journal of Pain
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• 제22권1호
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• pp.88-91
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• 2009

Skull base osteomyelitis is a rare but life-threatening complication of inflammation of the ear. The authors present a case of skull base osteomyelitis of unknown etiology in a non-diabetic patient who presented with unilateral posterior neck and occipital headache mimicking cervicogenic headache.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권6호
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• pp.484-487
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• 2012

Skull base osteomyelitis is a very rare disease that affects the bone marrow of the temporal bone, sphenoid bone, occipital bone. It occurs typically chronic ear canal infections by malignant otitis externa, but some of atypical osteomyelitis have been reported. It most commonly presents old diabetic patients, and have high morbidity and mortality rate if diagnosis and treatment are delayed. However with respect to pain or dysfunction, it appeared similar to the initial symptoms of temporomandibular joint disorder. So frequently, definitive diagnosis is tend to delayed. We have clinical experience that a patient who presented with symptom similar to temporomandibular disorder, and differential diagnosised by skull base osteomyelitis. We will report this case with literature review.

• 대한치과의사협회지
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• 제15권2호
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• pp.107-110
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• 1977

Class I malocclusion is essentially a dental dysplasia. Rotations, individual tooth malpositions, missing teeth, tooth size discrepancies, etc., fall under this classification. There are two types of class I malocclusions. One is identified by and insufficient denture base to accommodate the teeth; the other has more denture base than tooth material, creating spaces in the arch. The tooth material-to denture base discrepancies may be slight, calling for only a little increase in arch length for alignment and the correction of minor rotations. Discrepancies may also be great, in which case it becomes necessary to reduce tooth material by extraction, so as to make the tooth material more in proportion to the size of the denture base. The author had attempted orthodontic treatment of a class I malocclusion case of 13-year old boy in which high canines and impacted mandibular second premolars were involved. The author obtained good results.