흡착관을 이용한 자동차 에어컨 증발기의 냄새농축 방법

柳泳在 강원대학교 일반대학원 2009 국내석사

Recently, odor complaint has been increased for the malodor in the cars. Also, as a mechanical performance improved in the car, a pleasant air quality is required. Hence, the research has been conducted to resolve the problem of malodor and reduce the emission of air pollutants in the cars. It was generally known that the malodor was emitted from seat, sealant and plastic materials from the HVAC system in the cars, but according to the recent research, it was proved that the malodor is caused by evaporator in the air conditioning system. The operation modes in the air conditioning system can be divided into [Dry]mode, [Dry to wet]mode, [Wet]mode and [Wet to Dry] mode. Among those modes, the rapid changes of moisture occur at [Dry to Wet]mode and [Wet to Dry]mode leading to the occurrence of strong malodor. In contrast, odor was not sensed at the other modes. However, the odor causing compounds can be detected even though odor was not sensed. In addition, it is hard to examine the light-odor below detection limit and catch the time that odor is produced. Therefore, the new methods to condense the light-odor at continuous mode is required. To concentrate the light-odor, extremely low temperature condensing method and sorbent materials have been used. At extremely low temperature condensing method, high cost is required due to use of refrigerant. Meanwhile, in the case of sorbent materials, there are some advantages such as various types of sorbent materials in a sale, low cost and convenience to take samples. In this study, multi bed sorbent materials have been used for effective sampling and examination of light-odor below odor detection limit at [Dry]mode and [Wet]mode. Lab-scale test bench system (LTBS) used for experiment was similar to HVAC system in the real car system. Also, the amount of water produced from evaporator was almost similar between experimental bench system and real HVAC system in the cars. Generally, malodor was sensed with the rapid change of relative humidity showing the characteristic of LTBS, but it was not easy to reproduce same odor even when LTBS was operated at the same condition. Therefore, multi-bed adsorption tube made was used to condense light-odor for effective evaluation of non-detectable odor. Multi-bed adsorption tube made showed over 90% of recovery rate experiments and below 10% of RSD from the results of toluene . In addition, it was possible 14 times condensation of toluene indicating non-detectable odor limit. By using adsorption tube at [Dry]mode and [Wet]mode, the non-detectable odor was concentrated to 1 or 2 degree for direct odor sensory test and 3.2 and 3.6 times condensation for more than five carbon chains of volatile organic compounds. Also, the odor of "dusty" and "plastic" was detected from the samples obtained from [Wet to Dry]mode. The individual odor analysis showed that "dusty", "fragrant", "moldy" and "pungent" odor could be detected. Consequently, it was confirmed that the multi-bed adsorption tube was useful to concentrate non-detectable odor at various modes and reproduce the detectable odor for odor sensory test. 1) 이 연구에서 자동차 에어컨에서 발생하는 냄새를 평가하기 위해 사용된 냉동벤치 시스템은 실제 자동차의 냉방시스템과 유사한 성능을 나타냈다. 2) 냉동벤치 증발기에서 발생하는 불쾌한 냄새는 이전 연구 결과와 같이 증발기 표면의 상대습도 변화가 심할 때 발생하였으나, 냉동벤치를 가동할 때마다 항상 같은 냄새를 나타내지는 않았고, 냄새가 짧은 시간동안 순간적으로 발생하여 직접관능법 이외의 방법으로 평가하는데 어려움이 있었다. 특히 자동차 실내의 냄새를 제어하기위해 고려되고 있는 센서는 에어컨 증발기에서 발생하는 냄새를 평가할 수 없어 다른 방안의 강구가 필요하다. 3) 역치 이하의 냄새를 평가하기 위한 방법으로 검토된 triple-bed adsorption tube는 톨루엔에 대하여 Safe Sampling Volume이 약 49 L로 측정되었으며 톨루엔에 대한 회수율이 90% 이상으로 우수하였고, 재현성도 RSD 10% 이하로 양호하였다. 4) Triple-bed adsorption tube를 이용하여 톨루엔으로 제조한 역치이하의 냄새를 농축하여 평가한 결과 직접관능법과 공기희석관능법으로는 농축여부를 확인할 수 없었으나 TD-GC/FID로 분석한 결과 물질로서 약 14배 농축가능 하였다. 그리고 냉동벤치의 냄새가 나지 않았던 상시모드([Dry] mode와 [Wet] mode)에 적용하여 직접관능평가와 냄새값평가로 농축이 가능한 것을 확인 하였고, 물질로서도 농축된 것을 확인하였다. 5) Triple-bed adsorption tube를 이용하여 냄새가 발생하지 않는 냉동벤치의 상시모드에서 냄새를 농축하여 재현한 결과 직접관능평가로는 case 1의 경우 [Wet to Dry] mode에서 발생했던 “metal like", "plastic", "dusty"의 냄새 중 "plastic", "dusty" 냄새가 재현 되었다. 그리고 GC/FID/O의 개별냄새로 확인한 결과 case 1에서는 ”dusty", “fragrant"가 재현되었고, case 4에서는 ”plastic", "moldy", "pungent"가 재현되어 [Dry] mode와 [Wet] mode에서 발생하는 냄새를 농축하여 [Wet 세 Dry] mode에서 발생하는 냄새를 일부 재현하였다. 6) 이 연구에서 사용한 Triple-bed adsorption tube는 상시모드([Dry] mode, [Wet] mode)의 냄새를 농축하고, 냄새를 일부 재현하여 그 동안 수분 이내로 짧은 시간동안 발생하여 평가하기에 어려움이 있었던 [Wet to Dry] mode에서 발생하는 냄새 평가를 보완할 수 있었다. 그러나 에어컨에서 발생하는 냄새를 완전히 재현하지는 못하였기 때문에 용량이 더 큰 흡착관을 사용하여 농축량을 증가시켜 완전한 냄새의 재현을 이루거나 응축수에 있을 것으로 예상되는 냄새유발물질을 분석하여 보완할 필요가 있다.

암반사면과 절리의 주향차이를 고려한 안정성 해석 방법의 연구

유영재 서울시립대학교 일반대학원 2016 국내석사

암반사면의 파괴형태는 평면파괴, 쐐기파괴, 전도파괴, 원호파괴 등으로 구분할 수 있으며 각각의 파괴형태에 따른 파괴조건이 충족될 경우에 사면파괴가 일어날 확률이 높은 것으로 가정한다. 이러한 파괴조건을 판단하는 방법으로 사면과 절리에 대한 주향 / 경사와의 기하학적인 관계를 이용하는 평사투영법이 널리 쓰이고 있다. 평사투영법에서 평면파괴가 일어나기 위한 기하학적 조건으로 미끄러짐이 일어나는 면은 반드시 경사면에 평행하거나 거의 평행한(±20° 이내)주향을 가져야 한다고 제시되어 있으나, 거의 평행한 ±20°에 대한 공학적 근거는 제시되지 않고 있다. 평사투영법을 이용하여 파괴조건이 충족될 경우는 한계평형해석, 수치해석, 블록해석 등의 안정성해석방법을 이용 안전율을 정량화하여 암반사면의 안정성 및 보강방법을 검토한다. 본 연구를 위한 일정한 사면의 모델링에서 경사를 일정하게 유지하면서 주향의 변화를 주면 파괴블럭의 부피와 중량이 변화하고, 낙하하는 경사 또한 변화되므로 불연속면에서의 저항력과 활동력에 관계되는 안전율이 달라지는 것을 확인할 수 있었다. 그러나 안정성해석을 위해 널리 사용되고 있는 한계평형해석은 사면을 평형상태로 가정하여 해석하고 있지만, 사면과 불연속면의 주향이 다를 경우 발생하는 안전율의 변화는 고려하지 않고 있다. 본 연구에서는 한계평형해석의 가정 조건 중 사면과 절리의 평행조건 대한 한계점을 검증하였으므로 앞으로 사면 파괴에 대한 한계평형해석을 적용함에 있어 질적인 향상을 위한 기초 자료로 활용될 것으로 기대한다. The failure type of rock slope can be classified into plane failure, wedge failure, toppling failure, circular failure etc. and it is assumed that the probability that the slope failure occurs in case that failure conditions according to each failure type are met is high. As a method to judge these failure conditions, the stereographic projection using geometric relationship with strike/dip for a slope and a joint is widely used. As a geometric condition for a plane failure to occur in the stereographic projection, it is suggested that the side that a slide occurs must have a strike that is parallel or almost parallel (within ±20°) to the slope, but any engineering basis for the almost parallel ±20° is not presented. In case that failure conditions are met by using the stereographic projection. The stability and reinforcement method of a rock slope are reviewed by quantifying a safety factor by using the stability analysis methods such as the limit equilibrium analysis, the numerical analysis and the block analysis etc. If the strike is changed while maintaining a slope constantly at the modeling of the constant slope for this study, the volume and weight of the failure block are changed, and the falling slope is also changed so it can be confirmed that a safety factor that is related to resistance and activity on discontinuities is changed. However, the limit equilibrium analysis that is widely used for stability analysis analyzes with an assumption that a slope is in the state of equilibrium, but the variation of a safety factor that occurs in case that a strike of a slope and discontinuities is different is not considered. In this study, since the limit for parallel conditions of a slope and a joint among conditions of assumption for the limit equilibrium analysis is verified, it is expected that this will be utilized as basic data for qualitative improvement in applying the limit equilibrium analysis for the slope failure in the future.

(The) Effects of Involvement Load of Tasks and Exposure Frequency on L2 Vocabulary Learning of Korean Middle School Learners of English

유영재 서울대학교 대학원 2019 국내석사

Words are the basis of foreign language learning. Effective learning of more words in less time has been of great interest in Korean classroom situations where English is taught as a foreign language (EFL). Among many variables that influence vocabulary learning, the purpose of this study is to investigate the effects of two key factors that can be manipulated, task-induced involvement load and word exposure frequency, on second language (L2) vocabulary learning. Until now, there have been a few studies combining task involvement and word repetitions, and even few studies dealing with both variables have made contradictory conclusions regarding which factor is more important in vocabulary acquisition and retention. In addition, there is a limit in that the majority of the studies did not meet the minimum exposure to the target words, which is at least 6 times. Experiments were carried out with sixty 9th graders (43 advanced and 17 intermediate learners) by assigning them tasks with different task-induced involvement index and word repetitions. Two vocabulary tasks were completed at different times, with three glossed readings inducing less involvement, and one sentence-writing task inducing higher involvement load. All participants performed each task alternately in two sessions. Up to 12 word exposures for each target word were made in the reading task and 7 word repetitions in the writing task. At the end of each session, an immediate vocabulary retention test was taken, which consisted of active learning test and passive word test. As a result of two-way repeated ANOVAs, this study found that word exposure frequency had a greater effect on word acquisition than task-induced involvement load. If at least six sufficient word exposure conditions were met, three reading tasks with glosses resulted in better vocabulary retention effects than one sentence-writing task. In the overall test and the active word test, two different combinations of task-induced involvement load and word occurrences had a significant impact on word acquisition, but no significant effect on the passive word test. On the other hand, in relation to the learner's proficiency level, the higher learners showed better word acquisition than the intermediate learners in all the test types. In addition, regardless of the learner's level, all the participants showed a tendency to acquire the words significantly better in the condition of three reading tasks with glosses. Therefore, these consistent results provide teachers and material developers with pedagogical implications for effective vocabulary instruction in EFL contexts. 단어는 외국어 학습의 기본으로서, 많은 단어를 제한된 시간 내에 효율적으로 학습하는 방법은 영어를 외국어로 배우는 한국의 교실 상황에서 큰 관심사가 되어 왔다. 본 연구에서는 어휘 학습에 영향을 미치는 다양한 변인 가운데 통제 가능한 두 가지 변인인 과업관여도와 단어노출빈도가 한국 중학교 영어 학습자의 제2언어 어휘 학습에 미치는 영향을 연구하였다. 지금까지 과업관여도와 단어노출빈도 두 변인을 결합한 연구가 드물었고, 두 변인을 함께 다룬 연구조차 두 변인 중 무엇이 더 중요한지에 대해 상반된 결론을 내렸다. 또한 단어노출빈도도 유의미한 단어 학습이 일어나기 위한 최소한의 노출 요구치인 6 번을 충족하지 못한 연구가 대다수였다는 한계점이 있다. 본 연구는 60 명 (43 명의 상급 학습자와 17 명의 중급 학습자)의 한국 중학생 3 학년을 대상으로 6 주간 진행되었다. 두 가지 어휘 과업은 다른 횟수로 시행되었는데, 과업관여도가 낮은 주석 달린 읽기는 3 번, 과업관여도가 높은 쓰기 과업은 1 번 진행되었다. 모든 참여자들은 각각의 과업을 두 세션에서 번갈아 가며 수행하였다. 읽기 과업에서는 한 단어당 최대 12 번의 목표 단어 노출이, 쓰기 과업에서는 7 번의 단어 반복이 되었다. 각 세션의 마지막 시간에는 목표 단어에 대한 즉시 사후 평가가 시행되었다. 사후 평가는 적극적 단어 시험과 소극적 단어 시험으로 구성되었다. 이원반복분산분석을 실시한 결과, 과업관여도와 단어노출빈도 중 단어노출빈도가 단어 습득에 미치는 영향이 더 큰 것으로 나타났다. 최소 6 번 이상의 충분한 단어 노출 조건이 충족된다면 세 번의 읽기 과업이 한 번의 쓰기 과업보다 더 많은 단어 습득을 가져왔다. 또한 전체 시험과 적극적 단어 시험의 경우에는 과업관여도와 단어노출빈도의 다른 조합이 단어 습득에 유의미한 영향을 준 반면에, 소극적 단어 시험에서는 유의미한 영향이 나타나지 않았다. 한편 학습자의 수준과 관련하여 상급 학습자는 중급 학습자보다 모든 시험 유형에서 높은 단어 습득을 보였으며, 학습자의 수준에 관계없이 모든 참여자가 세 번의 읽기 과업에서 유의미하게 보다 높은 단어 습득의 경향을 보였다. 이와 같은 일관된 결과는 교사 및 교재개발자에게 학습자의 수준과 관계없이 효율적인 외국어 단어 지도 방안에 대한 시사점을 제공한다.

울산 앞바다의 환경조건을 적용한 부유식 해상풍력발전시스템의 부유체 비교연구

유영재 울산대학교 일반대학원 2020 국내석사

Korea plans to increase renewable energy production rate to 20% by 2030, under renewable energy policy 3020. This will involve 34% (16.5GW) from wind energy, among this the ratio of offshore wind generation is about 13GW. Floating offshore wind power must be considered to achieve this capacity. Floating offshore wind power can take advantage of wide sea areas, it is possible to build large wind farm. The design of floating offshore wind generators should take into account not only wind loads, but also complex marine environments such as wave and current load. However, there is not much research in Korea on floating offshore wind generators considering combined marine environmental conditions. In this study, we analyzed the environmental conditions of the East Sea, Korea. It’s 150m water depth and 58km from Ulsan port. The environmental condition analysis was performed on the meteorological agency’s oceanic meteorology buoy data, ERA-5 reanalysis data obtained from ECMWF, and NASA’s MERRA-2 data. The extreme sea states of 50 and 100 years were derived by extreme statistics analysis. Environmental conditions required for the basic design of floating offshore wind generators were selected following IEC and DNV standards. Using this result, a comparison was made between two type of floaters, spar and semi-submersible. Numerical simulations were performed using NREL FAST v8. Design load cases were selected by referring to IEC 61400-3. From the comparative results, we confirmed the characteristics of each floating platform under Korea East sea environment. 한국은 재생에너지 3020정책에 따라 2030년까지 재생에너지 발전 비중을 20%까지 올릴 계획을 하고 있다. 목표량 중 34% 정도를 풍력으로 감당할 계획이며, 해상풍력 발전 비중은 약 13GW가 된다. 이러한 발전 용량을 감당하기 위해서는 육상 및 고정식 해상풍력발전뿐만 아니라 부유식 해상풍력발전도 반드시 고려되어야 할 것이다. 부유식 해상풍력발전기는 기존의 고정식으로 설치되는 해상풍력발전기보다 더 광활한 바다 영역을 활용할 수 있으며, 육상이나 해안선을 따라 근해에 설치되는 풍력단지에 비해 대단지화가 가능한 장점이 있다. 풍력 자원 또한 육상보다 우수하며 운송이나 설치에 제약이 크게 없으므로 MW급이 높은 대형 풍력발전기도 설치가 가능하다. 이러한 부유식 해상풍력발전기의 설계를 위해서는 풍하중뿐만 아니라 파랑 하중과 해류 등의 복합 해상환경을 고려해주어야 한다. 그러나 아직 국내에는 복합 해상환경 조건을 고려한 부유식 해상풍력발전시스템에 대한 연구가 많이 없는 실정이다. 본 논문에서는 동해안의 환경자료를 사용하여 부유식 해상풍력발전기의 설계조건에 요구되는 환경 하중을 분석하였으며, 개념 설계 단계에서의 설계하중 값을 산출해보았다. 또한, 극치통계분석을 사용하여 50년 및 100년 주기의 극한 해상환경 조건을 산출하였다. 분석된 국내 해상 환경 조건에 기반하여 두 가지 형태의 부유체 반잠수식(Semi-submersible), 원통형(Spar) 부유체를 적용한 부유식 해상풍력발전시스템의 통합연성 해석을 수행하고 나타난 응답에 대해 비교연구를 수행하였다. 동해안의 설치 지점은 울산항으로부터 58km 떨어진 수심 150 m의 동해가스전 플랫폼의 반경 5km 해역을 선정하였으며, 수치해석은 미국 신재생에너지연구소 (NREL)에서 개발한 FAST v8을 사용하였다.

韓國繪畵에 나타난 소나무의 象徵性

유영재 충북대학교 교육대학원 2002 국내석사

모바일 로봇의 물체 파지 인식을 위한 셀프 라벨링 온라인 학습

유영재 서울대학교 대학원 2022 국내석사

동적인 환경에서 물체 파지를 정확하고 견고하게 하는 것은 모바일 조작 로봇이 성공적으로 과업을 수행하는데 필수적이다. 과거 암 로봇의 조작 연구에선 파지 인식을 위해 촉각 센서나 시각 센서를 사용하여 이를 해결하고자 했다. 하지만 이동형 로봇은 변화하는 환경에서 움직임으로 인해 노이즈가 발생함을 고려해야 한다. 최근 파지 인식 연구는 학습 기반 알고리즘에 의존하고 있다. 학습 기반 방법은 데이터를 수집하고 라벨을 입력하는데 많은 시간과 노력이 필요한 제한이 있다. 따라서 본 논문은 로봇의 파지인식학습을 위해, 스스로 라벨링을 수행하며 온라인 학습하는 과정을 자동화하는 종단간(end-to-end) 방법을 제시한다. 셀프 라벨링은 로봇이 물체가 파지 후 사라졌는지 여부를 카메라를 통한 물체 인식으로 확인하여 수행한다. 파지 인식은 멀티모달 파지 인식 네트워크를 통해 학습되며, 이때 입력 데이터는 카메라와 그리퍼의 여러 센서를 통해 얻은 데이터를 활용한다. 제안한 방법을 검증하기 위해 실내 거실 환경에서 정리정돈 과업을 수행하는 실험을 설계하였다. HSR 로봇을 활용해 11개의 물체를 정리정돈하는 두가지 비교실험을 진행하였고, 파지 인식 네트워크를 사용한 실험이 사용하지 않은 실험대비 파지 실패가 3회, 5회 발생했을 때 과업 수행 시간에서 각각 10.7%와 14.7%의 향상을 보여 제안한 방법의 효율성을 입증하였다. In this paper, we proposed a new grasp perception method for mobile manipulation robot that utilizes both self-labeling and online learning. Self-labeling is implemented by using object detection as supervision, and online learning was achieved by training the model with a randomly sampled batch from a queue-based memory. For robust perception, the GPN model is trained by processing four types of sensory data, and shows high accuracy in performance with various objects. To demonstrate our self-labeling online learning framework, we designed a pick-and-place experiment in a real-world environment with everyday objects. We verified the effectiveness of the GPN by a comparative experiment that measured the task performance by comparing time within two demos: one using the GPN-trained model, and the other using a simple logical method. As a result, it was confirmed that using the GPN does contribute in saving time for picking and placing the objects, especially if more failures occur, or the time spent in delivering the objects increases.

대나무 침염에 관한 연구

유영재 朝鮮大學校 大學院 1992 국내석사

Dyeing has been developed coexisting with the history of human developement. people might want to keep the color of nature which is changing gorgeously by seasonal variation. The history of dyeing might start from the people's desire to express the beauty on the textiles. People have used a not of natural and artificial dyes to satisfy their needs of living. Therfore, different kinds of dyes express each race and societies' custom, natural environment and cultural background. In this project, I would like to research about bamboo dyeing which is used as daily commodities. f will appoach using Dip-dyeing which is one of the major areas of dyeing art. Bambo has been used as the material for making daily acconnodities because of its nataural beauty and unque guality Althongh the manufacturing process of bamboo ware is differenciated by its usages, usually the colour and qualith in its nature has been used. Modern dyeing has had significient progress after the invention of artificial dyes, but in reality, the dyes has not tested sufficiently. Maintaining the art works for the longer time is the major concern of today's art. Almost all the historical art works has disappeared becauce of the lack of understanding about maintenance Therefore, people in present having difficutties to get sauces for their studying. The project is concerning about the dyeing methods, much specific methods to prevent, discoloration, and the conditions of dyeing method. I used the Damyang bamboos which is known as one of the best bamboos in Korea. I studied the bamboos as not a textile but a kind of woods. I studied their components and textures first and then the diffences of inner and outer sides of bamboo in dyeing. I wish my project will contribute to the abilith of progress in bamboo industrial product.

X-ray photoelectron diffraction study of ferroelectric distortion in epitaxially strained Pb(Zr0.2Ti0.8)O3 films

유영재 경희대학교 대학원 2016 국내석사

Recently, ferroelectric materials such as PbZrTiO3, BaTiO3 and PbTiO3 have been attracted as candidates for numerous applications such as non-volatile memories, photocatalysis and solar cells. Specially, Pb(Zr0.2Ti0.8)O3 has been treated the most used ferroelectric in applications, owing to its large ferroelectric polarization. However, an atomic scale sensitive technique is needed to get a more precise microscopic information on ferroelectricity and to be able to directly probe the ferroelectric polar distortion. Therefore, X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD) have been performed to understand surface chemistry and directly probe the intracell polar atomic distortion and tetragonality in epitaxial c-axis oriented Pb(Zr0.2Ti0.8)O3 films. There was a chemical reaction at surfaces as a function of oxygen vacancies and the evolutions of the core levels after annealing at high temperature. The XPD results show precise forward focusing maxima angles for each core level so that we derive the c/a ratio and demonstrate two oppositely polarized states.

고무계 개질재를 이용한 개질아스팔트의 최적반응조건 연구

유영재 수원대학교 대학원 2013 국내석사

Now, 70% of world wide pavement is damaged by plastic deformation and low-temperature cracking. So, road maintenance costs and driver safe is threatened. Also, waste tires are surrounding us, so they are needed to be recycled. Modification of asphalt with SBS and GTR improved strength and elasticity and anti-aging can be expected. Thus, asphalt life can be extended and our environment can be preserved by recycling of GTR. In this study DMP was used as a solvent as well as a modifier. DMP content in asphalt was constant at 5%. First, SBS was dissolved and GTR was swollen in DMP. Then, modification of asphalt was done using SBS, GTR and SBS/GTR by variety of temperature and time. Mechanical properties, rheological properties, thermo-sensitivity properties and antistripping ratio were measured. The results showed that optimum reaction conditions are 3 hours at 150 ℃ for the SBS series, 2 hours at 170 ℃ for the SBS/GTR series and 3 hours at 170 ℃ for GTR series.

β-Catenin 신호조절에 의한 백악질 형성 조절

유영재 전북대학교 일반대학원 2017 국내박사

Periodontal tissue is a functional unit supporting and encasing teeth. Cementum attaches each tooth to alveolar bone by embedding periodontal ligament adjacent to the surface of the tooth. Restoring lost periodontium, the ultimate goal of regenerative periodontal therapy, requires functional and anatomical reconstruction of a multitude of tissues including cementum, periodontal ligament, alveolar bone and gingiva. Recently, many studies on periodontal regeneration have been carried out, focusing on the regeneration or new attachment of damaged periodontal tissues. A specific concern for the clinician has been the limited predictability of cementogenesis, which is considered a prerequisite for complete restoration of periodontal tissues. Periodontal tissue generated during root formation. Toward the end of tooth crown development, epithelial cells from the enamel organ grow apically and form the Hertwig’s epithelial root sheath (HERS), an epithelial double cell layer indispensable for root formation. In this way, epithelial-mesenchymal interactions continue until completion of root development. While the root grows apically, more coronally located portions of the HERS disintegrate. Fragments of this disintegration process constitute the epithelial cell rests of Malassez (ERM), which reside in the periodontal ligament throughout life. The periodontal ligament arises from the dental follicle, an ectomesenchymal tissue encasing the developing tooth. Disintegration of HERS exposes the dentin surface and makes it accessible to other cells, for example, dental follicle cells. This is the moment when cementoblast differentiation starts and cementum matrix begins to be deposited on the exposed dentin surface. Cementogenesis importance of being known in the recent establishment of the periodontium. For example, periodontal ligament of attachment disorder is teeth due to cementum aplasia of metabolic disturbances, and will be caused an infection by bacterium. From those studies, it was found that the interactive functions of several biocontrol factors in cementum matrix play important roles in the regeneration and development of periodontal ligaments. It is well known that dental follicle cells of ectomesenchymal origin are capable of forming cementum when properly stimulated. As to the nature of the cementum forming cells (cementoblasts), there is a widely accepted opinion that they represent a population of periodontal cells, although some authors suggest that epithelial cells may also contribute to the process of cementum formation. To date, origin and differentiation mechanisms of cementoblast progenitors are unclear, and this is true for development and regeneration. Cellular and molecular mechanisms, which regulate formation of periodontal tissues, including cementum, have not been fully understood. To understand how the cementum formation during periodontal regeneration and development, and to make its application more concrete in regeneration, it is necessary to understand the mechanism at a sophisticated molecular level and also consider the control factors of specific functions. Among the various signaling factors, Wnt has been known to play an important role in forming periodontal tissue during the root development. Recently, dental researchers have focused on the potential role of Wnt signaling during morphogenesis of periodontal tissues. And β-Catenin is a key player in mediating epithelial- mesenchymal interactions during cementogenesis. As such, the HERS cell layer is important for regulating the initiation of cementum formation by control β-Catenin signaling in the cervical region where root development begins. The proliferation and differentiation of the enamel epithelium is believed to play an important role in normal growth of root and cementum formation. β-Catenin demonstrated the possibility of the initiation of early cementum layer formation by the extracellular matrix secretion of epithelial rests after HERS fragmentation, which contributed to root development in epithelial- mesenchymal interaction signal pathways. Osterox (Osx) regulates cementum formation by inhibit β-Catenin signal, and Smad4 is thought to play a role in the formation of the cementum through selective induction when embedding periodontal ligament fibers. We performed a tissue-specific control for β-Catenin, which plays a key role in the Wnt signaling pathway, in osteocalcin expression in odontoblast and cementoblast, and then identified the role of β-Catenin, the signal factors of Osx and Smad4, and interaction of cementum formation and the maintenance of periodontal tissue. Emerging regenerative strategies are promising to cure the irreversible damages to dental tissues, but the success of these strategies is constrained by the lack of insight on the molecular cues of regeneration, while recent advancements on the molecular controls of development of dental tissues provided valuable clues for identifying potential regenerative cues. These results support the concept that, during root development, the secreted products of the HERS induce adjacent cells of the periodontal ligament to differentiate and produce new cementum. Cementum formation is a key factor in the successful regeneration of periodontal tissue. It is believed that success induction of cellular cementum, rather than the cementum formation by selective induction, is more desirable for the regeneration of periodontal tissue and restoring proper cementum function.