Forged seal detection based on the seal overlay metric

Lee, J.,Kong, S.G.,Lee, Y.S.,Moon, K.W.,Jeon, O.Y.,Han, J.H.,Lee, B.W.,Seo, J.S. Elsevier Sequoia 2012 Forensic Science International Vol. No.

This paper describes a method for verifying the authenticity of a seal impression imprinted on a document based on the seal overlay metric, which refers to the ratio of an effective seal impression pattern and the noise in the neighborhood of the reference impression region. A reference seal pattern is obtained by taking the average of a number of high-quality impressions of a genuine seal. A target seal impression to be examined, often on paper with some background texts and lines, is segmented out from the background by an adaptive threshold applied to the histogram of color components. The segmented target seal impression is then spatially aligned with the reference by maximizing the count of matching pixels. Then the seal overlay metric is computed for the reference and the target. If the overlay metric of a target seal is below a predetermined limit for the similarity to the genuine, then the target is classified as a forged seal. To further reduce the misclassification rate, the seal overlay metric is adjusted by the filling rate, which reflects the quality of inked pattern of the target seal. Experiment results demonstrate that the proposed method can detect elaborate seal impressions created by advanced forgery techniques such as lithography and computer-aided manufacturing.

극한환경의 유체 누설 방지용 Double C-Type Seal 기계적 특성 파악

성지훈(Ji Hun Sung),노영진(Young Jin Roh),이선기(Seon Gi Lee),고기명(Gi Myeong Koh) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11

Sealing은 상대 면에 압력을 가하여 빈틈을 채워 Seal 주위로 가스나 유체가 새어나가는 것을 방지하는 것을 목적으로 한다(1). Seal은 사용환경에 맞게 고무, Teflon, Metal 등의 다양한 소재가 개발되어 사용되고 있다. 최근 들어 산업의 다양화, 복잡화로 인해 극저온, 고온, 고압 등의 조건을 요구하는 가스(수소), 화학공업, 우주항공산업 등에서 안전을 보장하기 위해 Seal 중요성이 더욱 대두되고 있다. 하지만 이러한 극한환경에서는 Non-Metal 소재의 Seal로는 본래의 기능을 만족시키기 어려워 Metal 소재를 이용해야 하는 것이 필요하다. 그리고 제품의 특성에 맞는 Metal Seal을 사용하기 위해서는 목적에 맞는 형상을 디자인하는 것이 중요하다. 본 연구에서는 범용적으로 사용되는 O-Type 및 C-Type Metal Seal의 형상을 보완하기 위하여 Double C-Type의 Metal Seal을 설계하였으며, 기존의 Metal Seal과 기계적 특성 해석을 통해 비교를 통해 기존 O-Type 및 C-Type Metal Seal의 장점은 향상되고, 단점은 보완되었음을 확인할 수 있었다. The purpose of sealing is to prevent gas or fluid from leaking around the seal by filling the gap by applying pressure to the opposite surface. Various materials such as rubber, Teflon, and metal have been developed and used for the seal according to the environment of use. Recently, due to the diversification and complexity of the industry, the importance of the seal is rising to ensure safety in the hydrogen industry, gas industry, chemical industry, nuclear power, and military industry that require conditions such as cryogenic temperature, high temperature, and high pressure. However, in such an extreme environment, it is necessary to use a metal material because it is difficult to satisfy the original function with a non-metal seal. And in order to use a metal seal suitable for the characteristics of the product, it is important to design a shape suitable for the purpose. In this study, double C-type metal seals were designed to complement the shapes of O-Type and C-Type metal seals used in general, and compared with existing metal seals through mechanical characteristic analysis. Through the comparison results, it was confirmed that the advantages of the existing O-Type and C-Type metal seals were improved and the disadvantages of the double C-type metal seals were improved.

C 형 금속 씰링 장치 성능시험을 위한 불확도 추정 연구

성지훈(Ji Hun Sung),이선기(Seon Gi Lee),노영진(Young Jin Roh),고기명(Gi Myeong Koh) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

Sealing의 사전적 의미는 내부로부터의 누설, 외부로부터의 침입을 방지하기 위한 장치로, 운동부의 Seal 은 Packing, 고정부의 Seal 은 Gasket이라 한다. 서로 접촉한 부분에서 유체의 누설을 방지하기 위한 밀봉장치인 씰(Seal)은 접촉하는 기계 부분의 각종 조건, 상태에 따라 적합한 것을 선택하는 것이 필요하다(1). 최근 수소, LNG, 우주항공 등의 산업이 발달하면서 고온/극저온, 고압과 같은 극한 환경에 대한 안전성을 확보하기 위해 Sealing 기술의 중요성이 대두되고 있다. 예를 들어 LNG 선박의 경우 영하 162℃의 극저온의 환경에서 Sealing을 확보하기 위해 Metal Seal Ring을 사용하여야 한다. 이러한 Seal Ring의 건전성을 확보하기 위한 성능시험이 수행되어야 하지만 현재로서는 명확한 시험 표준이 마련되어 있지 않아 시험 기관에서도 시험결과에 대한 신뢰성을 확보하는데 어려움이 있다. 시험결과의 신뢰성을 확보하기 방법으로는“ISO/IEC GUIDE 98-3(측정불확도 표현지침) (2)”에 따라 측정불확도를 산출하는방법이 있으며, 이러한 측정불확도 산출은 시험에 대한 신뢰성을 국제적으로 인정받고 있는 KOLAS(한국인정기구)에서도 동일하게 적용하고 있는 방법이다. 따라서 본 논문에서는 C 형 Metal Seal Ring의 성능시험 결과의 신뢰성 확보를 위해 국제표준(ISO)에 따른 측정불확도 산출을 위한 불확도 요인 인자를 선정함으로써 앞으로 수행하는 Metal Seal Ring의 성능시험 결과의 신뢰성이 향상될 수 있는 방안을 제시하고자 한다. The dictionary meaning of sealing is to prevent leakage from the inside and intrusion from the outside. The sealing of the exercise part is called packing, and the sealing of the fixing part is called gasket. It is necessary to select an appropriate seal, which is a sealing device for preventing fluid leakage from the parts that come into contact with each other, according to various conditions and conditions of the mechanical parts that come into contact with each other ⁽¹⁾. With the recent development of industries such as hydrogen, LNG, and aerospace, the importance of sealing technology has emerged to ensure safety for extreme environments such as high temperature/extreme low temperature and high pressure. For example, for LNG vessels, metal seal rings should be used to secure sealing in a cryogenic environment of minus 162℃. Performance tests should be performed to ensure the integrity of these seal rings, but there are currently no clear test standards, making it difficult for test institutions to ensure reliability of test results. The method to secure reliability of test results is to calculate measurement uncertainty in accordance with ISO/IEC GUIDE 98-3 ⁽²⁾. This measurement uncertainty calculation is applied equally to the internationally recognized KOLAS (Korean Accreditation Organization). Therefore, in this paper, the reliability of the performance test results of the C-type Metal Seal Ring can be improved by selecting uncertainty factors to calculate measurement uncertainty according to the International Standard (ISO).

라비린스 실, 브러쉬 실, 반경 필름 라이딩 페이스 실의 누설 측정

정진우,황성호,김태호,김어진,하진웅 한국유체기계학회 2023 한국유체기계학회 논문집 Vol.26 No.4

Seals play a role in reducing and controlling leakage flows in a gap between rotating and stationary parts, thus improving energy efficiency in various fluid machinery such as gas turbines, steam turbines, turbocompressors, and turbopumps. In general, there are two types of seals: contact seal and non-contact seal for rotating machinery. The contact seal has the advantage of low leakage, but there is a risk of damage to parts due to friction caused by the contact between the rotor and the stator. In the case of the non-contact seal, damage to parts does not occur because there is no friction, but there is a concern that a large amount of leakage may occur. A hybrid seal uses both the advantages of the non-contact and contact seals by using hydrostatic pressure and hydrodynamic pressure effects to form a small gas film between the rotor and stator. The purpose of this study is to measure the leakage flow rates of the contact seal (Labyrinth seal), non-contact seal (Brush seal), and hybrid seal (Radial Film riding face seal). The paper details the rotordynamic characteristics of a rotating test rig for the leakage measurements the test seals at high speeds and the comparison of the measured leakage flows at non-rotating and rotating conditions. In addition, rotor coastdown tests from 10,000 rpm reveal the frictional characteristics of the tests seals.

葦滄 吳世昌의 篆刻과 印譜

이승연 한국서지학회 2008 서지학연구 Vol.41 No.-

Wichang,(葦滄) Oh Se-chang(吳世昌) who laid the foundation stone of Korean art history was a compiler, a calligrapher, a bibliographer and a great epigrapher. He also was a great seal engraver who sublimated the engraving into the art and made the big stroke in Korean modern history of engraving. He started to study by himself the seal engraving from his late teens by copying the collections of the past Chinese seal prints(印譜) that his father had collected through his thirteen trips to China as an official interpreter. He copied the past Chinese and Korean seal prints, and also enjoyed the seal engraving holding the seals in his hands through his whole life. Wichang’s fascination with the seal engraving since his youth was further encouraged by the lively activity of Japanese seal engraving community which he had observed during his exile in Japan. After returning to Korea, he could give himself to the seal engraving. He accepted various forms of expression that the engravers of the Ching Period in China had applied to select the materials and forms of seals, makers’ signs and seals on the bells or kettles, Wadang(瓦當), Jeonpyeoe(錢幣), Bongni(封泥), etc, to Inmun(印文) of seals. Accordingly, he could hold an unrivalled position as the master of engraving with his own unique style as well as the style of Japanese chisel. His engraving accepted various styles of scholars in the Ching age and was influenced by Chusa’s view of seal engraving and academic circles. Wichang, while dedicating his time to seal engraving, also did a lot of research on this subject to collect 3,912 articles of the past Korean seals and complie 「Geunyeokinsu(槿域印籔)」. He also compiled 7 collections of his own seal prints such as 「Wichanginbo(葦滄印譜)」, 「Ohssiinjip(吳氏印集)」, etc. These collections can be considered the remarkable achievement as one of the rare collections as well as the very first individual collection of a devoted seal engraver since the seal print collection of Chusa. Since he succeeded the artistic value and spirit of seal engraving established since the period of Chusa and bridged between the modern period and the present, his tremendous impact on the seal engraving could be fully appreciated. 葦滄 吳世昌(1864~1953)은 한국미술사의 초석을 이룬 편저자, 서화가, 고증학자, 금석학자일뿐만 아니라, 전각을 예술로 승화시켜 근대 전각사에 큰 획을 그은 전각가이다. 그는 10대 후반부터 부친 오경석이 역관으로서 13차례나 중국을 왕래하며 수집한 중국의 역대 印譜와 한국의 印譜들을 보고 스스로 模刻을 통한 전각공부를 시작하여 평생을 손에서 印材를 놓지 않고 작품을 즐겨하였다. 이렇게 위창이 전각에 심취할 수 있었던 것은 어려서 부터 형성된 전각관이 일본 망명시절 일본전각계의 활발한 활동에 자극 받아 본격적으로 매달렸으며, 고증학에 의한 淸代 篆刻家들의 다양한 印材 취택과 형식, 鍾鼎款識와 瓦當ㆍ錢幣ㆍ封泥 등을 인문에 사용하는 표현양식을 받아 들여 일본의 刀風과 함께 독창적인 전각세계를 이루었다. 따라서 위창의 전각은 청대 각 유파들의 각풍 수용과 추사의 학맥, 전각관의 영향이 컸으며, 이러한 예술관을 가지고 역대 한국ㆍ중국ㆍ일본 인보를 두루 섭렵하여 자가풍이 이루어졌다고 할 수 있다. 위창은 창작과 더불어 전각에 관한 연구를 깊이하여 우리나라의 역대 인장 3,912顆를 모아 槿域印藪를 편집하였으며, 自刻한 인장을 모아 「葦滄印譜」ㆍ「吳氏印集」 등 7종의 印譜를 직접 엮어서 남기고 있다. 이는 추사인보 이후 인보가 흔치 않았던 전각계에 한 획을 긋는 업적이며, 순수한 자각인으로서는 최초의 인보로써 의미가 크다고 하겠다. 이후 추사 이래 전각에 대한 예술적인 가치부여가 형성된 이후의 맥을 잇는 전각가가 되었으며, 近代와 現代의 전각계를 잇는 교량 역할을 하게 되어 후대 전각계에 미친 영향은 지대하다고 할 수 있다.

Characterising the dynamic seals used in absorber rod drive mechanisms in Indian FBR

Kaushal, Nihal,Patri, Sudheer,Kumar, R. Suresh,Meikandamurthy, C.,Sreedhar, B.K.,Murugan, S.,Raghupathy, S. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.10

Dynamic seals are one of the critical components of Absorber Rod Drive Mechanism of Fast Breeder Reactors, requiring separate experimental development. Their significance can't be overemphasized considering that the availability and re-usability of Control Rod Drive Mechanisms of Fast Breeder Test Reactor is governed by the failure rate of dynamic seals (bellows). For prototype and subsequent Fast Breeder Reactors in India, choice of the dynamic seal is changed to an in-house designed & developed labyrinth type V-ring seal. The present work is related to the numerical investigations carried out to gain insights into the sealing mechanism and the thermal behaviour of these seals. The results indicate that the seal geometry is very important for obtaining optimum performance. By changing the geometry of the present seal, performance enhancement by more than 50% in important indices is obtained. Further, the results point out that caution shall be exercised when the seal material & its operating temperature are changed. Also, the numerical model developed in this study will be useful for developing more robust dynamic seals in future.

A Study on Improving the National Safeguards Seals for the Wolsong Spent Fuel Dry Storage Facility

Sungho Yoon 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

A seal is one of the primary means of safeguards along with surveillance. The International Atomic Energy Agency (IAEA) uses various types of seals to verify the diversion of nuclear materials and is developing new seals according to the development of technology. Independent of the IAEA, ROK uses national safeguards seals for state-level regulation. A national safeguards inspector binds the nuclear material storage by combining a seal with a metal wire and checks the serial number of the RFID chip inserted in the seal with a reader. The Wolsong spent fuel dry storage facility has 14 modules, each with 24 seals, and thus a maximum of 336 national seals will be installed. Although dependent on the sealing method, it takes about 5 minutes to verify one seal. As such, a considerable workforce is required for verification, and both the IAEA and the ROK are currently conducting random inspections. In addition, there are cases where verification is impossible because old seals are damaged due to harsh environments and long exchange periods. Therefore, in this study, we analyzed cases in areas where sealing technology has been developed to improve the problems of the existing national safeguards seals. And we proposed a method for improving national seals by finding requirements of seals considering spent fuel dry storage facility characteristics. In international logistics, sealing is essential in product transport verification, terrorism prevention, and tariff imposition. Accordingly, the field of container sealing has been extensively developed, and the International Organization for Standardization (ISO) has regulated the mechanical requirements of the seal as ISO 17712 and the electronic requirements as ISO 18185. Mechanical seals include metal and plastic seals and metal seals include bolt seals, ball seals, and cable seals. In addition, there are various electronic seals, such as radio frequency identification (RFID), near field communication (NFC), infrared (IR). Recently, there has been a trend to use active seals that have a built-in battery and can implement various additional functions. Among the various seals, the main requirements for selecting seals suitable for dry storage facilities are as follows. First, use of a sealing tube longer than 10m should be possible. Second, it should have corrosion resistance so that it can be used for more than five years in the coastal area. Third, it must be a passive seal without a power supply. Fourth, it should not be overly costly. Finally, the seal verification time should be short. As a seal that satisfies these requirements, an electronic seal with application of the passive RFID method to the mechanical form of a metal cable seal is suitable. Since it is not an active seal, it is difficult to determine the time of breakage. Therefore, designing the seal such that the RFID is also damaged when the metal seal is broken will be helpful for verification. In this study, the requirements for national safeguards seals in dry storage facilities were defined, and measures to improve the existing national seals were studied. Field applicability will be evaluated through future sealing device design and demonstration tests.

Improvement Research on Sealing Performance of Oil Seal

란준 한국특허학회 2016 특허학연구 : 한국특허학회지 Vol.17 No.2

In the mechanical operation, the friction between the bearing and oil seal will lead to oil temperature increasing and cracking and produce painting film by acidic substances and PTFE surface, resulting in failure of oil seal. In order to realize the temperature decreasing of the lubricating oil flowing andavoid oil seal failure due to the rise of temperature and improve the sealing performance of oil seal, thread groove is carved in the oil seal lip to let the oil film produce the inward suction.

A Study of Magnetic Fluid Seals for Blood Sealing

Jun TOMIOKA,Akira FUKAISHI,Takashi OHBA 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.2002 No.10

Magnetic fluid seals are used in a wide variety of gas and dust sealing applications. However, it is difficult to seal for liquid because of its characteristic. This study will be a basic guide for a magnetic fluid seal for liquid, especially for blood to be practically used in medical instruments such as rotary blood pumps by clarifying its seal properties. Sealing pressure test, durability test, and hemolysis test have been conducted for this seal. In this study, magnetic fluid, sealing fluid, eccentricity ratio, revolution speed were selected as parameters. As results of the tests, it has been found that the properties of magnetic fluid seal depend on the solvent and the saturation magnetization of magnetic fluid. Therefore, the selection of magnetic fluid is important for this seal. It also has been found that eccentricity ratio of the shaft caused harmful effect for seal propertles. In conclusion, it has been showed that magnetic fluid seals could be possibly used in medical instruments such as blood pumps when blood come in contact with magnetic fluids.

佛印과 塔印 등, 印의 한국 수용과 전개

문상련 동악미술사학회 2023 東岳美術史學 Vol.- No.34

본 논문은 고려와 조선시대 간행의 다라니에 실린 佛印과 塔印 등 印의 수용과 전개를 서술한것이다. 먼저 경전에 근거해 印과 佛印의 개념을 설명했으며, 중국에서 형성된 불인과, 부처의 內 在性을 형상화한 種字가 佛印化되는 양상을 서술하였다. 또한 한국의 경우 삼국 이래 佛印과 塔印의 수용 양태를 서술했으며, 고려, 조선시대의 간행다라니에 실린 3종 佛印과 1종의 塔印, 그리고 舍利甁印이라 칭할 수 있는 印 등 5종의 印이 형성되는 과정과 함께, 진언의 佛印化를 통해 새로운 印이 성립되었음을 말하였다. 이에 고려와 조선 전기의 경우, ‘불정심인’과 ‘비로자나인’ 등 2종의 불인이 주로 사용되었으며, 조선 초에는 탑인이 추가된 예를 설명하였다. 이후 15세기 후반 16세기 이래, 2종의 불인과 탑인외에 ‘석가여래화압’이 추가되었으며, 『성관자재구수육자선정』에 실린 ‘옴 치림’과 ‘옴 부림’, ‘옴 타림’ 등 3종 불인을 통해 진언이 종자화, 佛印化되는 과정을 통해 불인이 다양화되는 예를 언급하였다. 이외에 새로운 印으로서 ‘舍利甁印’의 형성과 함께, 印은 다라니 안에서 부적의 한 예로 자리했다가, 차츰 부적에 비해 우월한 위치를 차지하게 되었음을 언급하였다. This thesis examines the adoption and development of the Buddhist seals (in) in the Goryeo and Joseon periods as represented by the “Buddha’s seals” (burin) and “pagoda seals” (tabin) contained in the dharanis published in Goryeo and Joseon. The main discussion starts with an introduction of the seal and the Buddhist seal based on texts in the Buddhist scriptures, and continues with the Buddhist seals developed in China and the process by which the “seed syllables” representing the internality of Buddha developed into Buddhist seals. The following discussion focuses on Korea and how both the Buddha’s seal and the pagoda seal were introduced there during the Three Kingdoms period. It also addresses the process of development of five types of Buddhist seals, three Buddha’s seals, and one pagoda seal contained in Goryeo and Joseon dharanis, and another that can be called the “sarira bottle seal”, as well as the establishment of a new seal created through the transition from the mantras. The discussion then turns to the fact that the Buddhists of Goryeo and early Joseon used two types of Buddha’s seal, the “usnisa heart seal” and the “Vairocana’s seal”, and later introduced the pagoda seal. It also shows that two more Buddha and pagoda seals, plus the “Shakyamuni’s floral seal”, were introduced between the late fifteenth and late sixteenth centuries, and that Buddhist seals became more diverse in this period through the process by which mantras - particularly the three (om chirim, om burim, and om tarim) contained in the Meditation Based on the Six-character Mantra of the Sacred Bodhisattva of Spontaneous Contemplation - developed into “seed syllables” and, finally, the Buddha’s seal. Finally, the discussion focuses on the creation of the sarira bottle seal, concluding that it was originally established as a form of talisman in the dharanis, but was gradually raised to a superior status.