• Title/Summary/Keyword: IT Proposal

Search Result 1,895, Processing Time 0.041 seconds

A Proposal for Simplified Velocity Estimation for Practical Applicability (실무 적용성이 용이한 간편 유속 산정식 제안)

  • Tai-Ho Choo;Jong-Cheol Seo; Hyeon-Gu Choi;Kun-Hak Chun
    • Journal of Wetlands Research
    • /
    • v.25 no.2
    • /
    • pp.75-82
    • /
    • 2023
  • Data for measuring the flow rate of streams are used as important basic data for the development and maintenance of water resources, and many experts are conducting research to make more accurate measurements. Especially, in Korea, monsoon rains and heavy rains are concentrated in summer due to the nature of the climate, so floods occur frequently. Therefore, it is necessary to measure the flow rate most accurately during a flood to predict and prevent flooding. Thus, the U.S. Geological Survey (USGS) introduces 1, 2, 3 point method using a flow meter as one way to measure the average flow rate. However, it is difficult to calculate the average flow rate with the existing 1, 2, 3 point method alone.This paper proposes a new 1, 2, 3 point method formula, which is more accurate, utilizing one probabilistic entropy concept. This is considered to be a highly empirical study that can supplement the limitations of existing measurement methods. Data and Flume data were used in the number of holesman to demonstrate the utility of the proposed formula. As a result of the analysis, in the case of Flume Data, the existing USGS 1 point method compared to the measured value was 7.6% on average, 8.6% on the 2 point method, and 8.1% on the 3 point method. In the case of Coleman Data, the 1 point method showed an average error rate of 5%, the 2 point method 5.6% and the 3 point method 5.3%. On the other hand, the proposed formula using the concept of entropy reduced the error rate by about 60% compared to the existing method, with the Flume Data averaging 4.7% for the 1 point method, 5.7% for the 2 point method, and 5.2% for the 3 point method. In addition, Coleman Data showed an average error of 2.5% in the 1 point method, 3.1% in the 2 point method, and 2.8% in the 3 point method, reducing the error rate by about 50% compared to the existing method.This study can calculate the average flow rate more accurately than the existing 1, 2, 3 point method, which can be useful in many ways, including future river disaster management, design and administration.

Possibility of Establishing an International Court of Air and Space Law (국제항공우주재판소의 설립 가능성)

  • Kim, Doo-Hwan
    • The Korean Journal of Air & Space Law and Policy
    • /
    • v.24 no.2
    • /
    • pp.139-161
    • /
    • 2009
  • The idea of establishing an International Court of Air and Space Law (hereinafter referred to ICASL) is only my academic and practical opinion as first proposal in the global community. The establishment of the International Court of Air and Space Law can promote the speed and promote fairness of the trial in air and space law cases. The creation of an ICASL would lead to strengthening of the international cooperation deemed essential by the global community towards joint settlement in the transnational air and space cases, claims and would act as a catalyst for the efforts and solution on aircraft, satellite and space shuttle's accidents and cases and all manpower, information, trial and lawsuit to be centrally managed in an independent fashion to the benefit of global community. The aircraft, satellite and spacecraft's accidents attributes to the particular and different features between the road, railway and maritime's accidents. These aircraft, satellite and spacecraft's accidents have incurred many disputes between the victims and the air and space carriers in deciding on the limited or unlimited liability for compensation and the appraisal of damages caused by the aircraft's accidents, terror attack, satellite, space shuttle's accidents and space debris. This International Court of Air and Space Law could hear any claim growing out of both international air and space crash accidents and transnational accidents in which plaintiffs and defendants are from different nations. This alternative would eliminate the lack of uniformity of decisions under the air and space conventions, protocols and agreements. In addition, national courts would no longer have to apply their own choice of law analysis in choosing the applicable liability limits or un-limit for cases that do not fall under the air and space system. Thus, creation of an International Court of Air and Space Law would eliminate any disparity of damage awards among similarly situated passengers and shippers in nonmembers of air and space conventions, protocols, agreements and cases. Furthermore, I would like to explain the main items of the abovementioned Draft for the Convention or Statute of the International Court of Air and Space Law framed in comparison with the Statute of the International Court of Justice, the Statue of the International Tribunal for the Law of the Sea and the Statute of the International Criminal Court. First of all, in order to create the International Court of Air and Space Law, it is necessary for us to legislate a Draft for the Convention on the Establishment of the International Court of Air and Space Law. This Draft for the Convention must include the elected method of judges, term, duty and competence of judge, chambers, jurisdiction, hearing and judgment of the ICASL. The members of the Court shall be elected by the General Assembly and Council of the ICAO and by the General Assembly and Legal Committee of the UNCOPUOS from a list of persons nominated by the national groups in the six continent (the North American, South American, African, Oceania and Asian Continent) and two international organization such as ICAO and UNCOPUOS. The members of the Court shall be elected for nine years and may be re-elected as one time. However, I would like to propose a creation an International Court of Air and Space Law in extending jurisdiction to the International Court of Justice at the Hague to in order to decide the air and space convention‘s cases. My personal opinion is that if an International Court on Air and Space Law will be created in future, it will be settled quickly and reasonably the difficulty and complicated disputes, cases or lawsuit between the wrongdoer and victims and the injured person caused by aircraft, satellite, spacecraft's accidents or hijacker and terrorists etc. on account of deciding the standard of judgment by judges of that’s court. It is indeed a great necessary and desirable for us to make a new Draft for the Convention on a creation of the International Court of Air and Space Law to handle international air and space crash litigation. I shall propose to make a new brief Draft for the Convention on the Creation of an International Court of Air and Space Law in the near future.

  • PDF

The Effect of Active Senior's Career Orientation and Educational Entrepreneurship Satisfaction on Entrepreneurship Intention and Entrepreneurship Preparation Behavior (액티브 시니어의 경력지향성과 창업교육 만족이 창업의지와 창업준비행동에 미치는 영향)

  • Park, Joungbum;Yang, Youngseok;Kim, Myungseuk
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.15 no.1
    • /
    • pp.285-301
    • /
    • 2020
  • Looking at the problem of aging in the nation from a demographic perspective, it is not a problem of the overall population, but of the structure of the population. It is the baby boomer and post-baby boomers, the largest population in the country. Baby boomers were born between 1955 and 1963, and currently have a population of 7001,333, which is 13.6 percent (as of 2015). The Post-Baby Boomer generation was born between 1964 and 1974, with a total population of 9,567,171, accounting for 18.8 percent of the total population. In particular, baby boomers and post-baby boomers (32.4% of the total population) have begun to retire or will retire soon. The average life expectancy continues to increase due to the development of medical technology, and the falling birth rate of newborns and the declining population of the production population are darkening the domestic economy. In a policy proposal aimed at easing the nation's falling economic growth rate, women's participation rate is as high as Sweden and men's efforts to increase it as high as Japan's, while the elderly rate is desirable to maintain Korea's high level. This is because the expansion of the elderly generation's participation in economic activities could ease a sharp drop in economic growth and reduce the burden of supporting the elderly population. The study, based on this social problem awareness and problem solving plan, looks at the relationship between career orientation and satisfaction in start-up education based on the diverse career base of active seniors, and also suggests the importance of customized start-up education on the diversity of active seniors by clarifying the relationship between them, and suggests the desirable direction of senior start-up policy design, funding, and start-up education. Based on the theoretical background, the concept of five factors was defined: active senior, career-oriented, satisfaction level of start-up education, willingness to start a business, and the concept definition of an active senior, which is particularly key to the baby boomers in their 50s and 60s, is generally regarded as a source of consumption or welfare benefits, but in this study, the concept of active start-up is reflected in the domestic start-up market by young people in their 40s, 50s and 60s. As a result of a hypothesis test. Hypothesis 1 and Hypothesis 5: Career orientation has been verified to affect the willingness to start a business and the behavior of preparation for a start-up. Hypothesis 3: The willingness to start a business has been verified as having an effect between startup preparation actions. Hypothesis 4: The satisfaction level of start-up education has been verified to affect start-up preparation behavior. However, hypothesis 2: The satisfaction level of education for start-ups does not affect the willingness to start a business. Such results can be inferred that satisfaction in start-up education does not have a direct effect on the will to start a business and increases the will to start a business through the influence of personal career orientation.

The Effect of Expert Reviews on Consumer Product Evaluations: A Text Mining Approach (전문가 제품 후기가 소비자 제품 평가에 미치는 영향: 텍스트마이닝 분석을 중심으로)

  • Kang, Taeyoung;Park, Do-Hyung
    • Journal of Intelligence and Information Systems
    • /
    • v.22 no.1
    • /
    • pp.63-82
    • /
    • 2016
  • Individuals gather information online to resolve problems in their daily lives and make various decisions about the purchase of products or services. With the revolutionary development of information technology, Web 2.0 has allowed more people to easily generate and use online reviews such that the volume of information is rapidly increasing, and the usefulness and significance of analyzing the unstructured data have also increased. This paper presents an analysis on the lexical features of expert product reviews to determine their influence on consumers' purchasing decisions. The focus was on how unstructured data can be organized and used in diverse contexts through text mining. In addition, diverse lexical features of expert reviews of contents provided by a third-party review site were extracted and defined. Expert reviews are defined as evaluations by people who have expert knowledge about specific products or services in newspapers or magazines; this type of review is also called a critic review. Consumers who purchased products before the widespread use of the Internet were able to access expert reviews through newspapers or magazines; thus, they were not able to access many of them. Recently, however, major media also now provide online services so that people can more easily and affordably access expert reviews compared to the past. The reason why diverse reviews from experts in several fields are important is that there is an information asymmetry where some information is not shared among consumers and sellers. The information asymmetry can be resolved with information provided by third parties with expertise to consumers. Then, consumers can read expert reviews and make purchasing decisions by considering the abundant information on products or services. Therefore, expert reviews play an important role in consumers' purchasing decisions and the performance of companies across diverse industries. If the influence of qualitative data such as reviews or assessment after the purchase of products can be separately identified from the quantitative data resources, such as the actual quality of products or price, it is possible to identify which aspects of product reviews hamper or promote product sales. Previous studies have focused on the characteristics of the experts themselves, such as the expertise and credibility of sources regarding expert reviews; however, these studies did not suggest the influence of the linguistic features of experts' product reviews on consumers' overall evaluation. However, this study focused on experts' recommendations and evaluations to reveal the lexical features of expert reviews and whether such features influence consumers' overall evaluations and purchasing decisions. Real expert product reviews were analyzed based on the suggested methodology, and five lexical features of expert reviews were ultimately determined. Specifically, the "review depth" (i.e., degree of detail of the expert's product analysis), and "lack of assurance" (i.e., degree of confidence that the expert has in the evaluation) have statistically significant effects on consumers' product evaluations. In contrast, the "positive polarity" (i.e., the degree of positivity of an expert's evaluations) has an insignificant effect, while the "negative polarity" (i.e., the degree of negativity of an expert's evaluations) has a significant negative effect on consumers' product evaluations. Finally, the "social orientation" (i.e., the degree of how many social expressions experts include in their reviews) does not have a significant effect on consumers' product evaluations. In summary, the lexical properties of the product reviews were defined according to each relevant factor. Then, the influence of each linguistic factor of expert reviews on the consumers' final evaluations was tested. In addition, a test was performed on whether each linguistic factor influencing consumers' product evaluations differs depending on the lexical features. The results of these analyses should provide guidelines on how individuals process massive volumes of unstructured data depending on lexical features in various contexts and how companies can use this mechanism from their perspective. This paper provides several theoretical and practical contributions, such as the proposal of a new methodology and its application to real data.

A proposal of soft tissue landmarks for craniofacial analysis using three-dimensional laser scan imaging (3차원 레이저 스캔을 이용한 안면 연조직 분석을 위한 계측점의 제안)

  • Baik, Hyoung-Seon;Lee, Hwa-Jin;Jeon, Jai-Min
    • The korean journal of orthodontics
    • /
    • v.36 no.1 s.114
    • /
    • pp.1-13
    • /
    • 2006
  • Three-dimensional (3-D) laser scans can provide a 3-D image of the face and it is efficient in examining specific structures of the craniofacial soft tissues. Due to the increasing concerns with the soft tissues and expansion of the treatment range, a need for 3-D soft tissue analysis has become urgent. Therefore, the purpose of this study was to evaluate the scanning error of the Vivid 900 (Minolta, Tokyo, Japan) 3-D laser scanner and Rapidform program (Inus Technology Inc., Seoul, Korea) and to evaluate the mean error and the magnification percentage of the image obtained from 3-D laser scans. In addition, soft tissue landmarks that are easy to designate and reproduce in 3-D images of normal, Class II and Class III malocclusion patients were obtained. The conclusions are as follows; scanning errors of the Vivid 900 3-D laser scanner using a manikin were 0.16 mm in the X axis, 0.15 mm in the Y axis, and 0.15 mm in the Z axis. In the comparison of actual measurements from the manikin and the 3-D image obtained from the Rapidform program, the mean error was 0.37 mm and the magnification was 0.66%. Except for the right soft tissue gonion from the 3-D image, errors of all soft tissue landmarks were within 2.0 mm. Glabella, soft tissue nasion, endocanthion, exocanthion, pronasale, subnasale, nasal alare, upper lip point, cheilion, lower lip point, soft tissue B point, soft tissue pogonion, soft tissue menton and preaurale had especially small errors. Therefore, the Rapidform program can be considered a clinically efficient tool to produce and measure 3-D images. The soft tissue landmarks proposed above are mostly anatomically important points which are also easily reproducible. These landmarks can be beneficial in 3-D diagnosis and analysis.

The Critical Thinking of Philosophy as a Creative Method of Science: Neurophilosophical Explication (창의적 과학방법으로서 철학의 비판적 사고: 신경철학적 해명)

  • Park, Jeyoun
    • Journal of The Korean Association For Science Education
    • /
    • v.33 no.1
    • /
    • pp.144-160
    • /
    • 2013
  • This study is a proposal, which is the trial to explicate, in neurology, on how critical thinking as a creative method of sciences functions. The creative methods of sciences, even at present, are mostly the hypothetical insistences concerning with the logical processes of researches suggested from the philosophers of science; Popper, Kuhn, Hempel, or Lakatos. These insistences do excavate what process or approach can be scoped out of scientists' creativity. I call the tendency or approach of the researches, "Process Approach of Creativity (PAC)". From my view point, any PAC trial does not concern with how creative theories can actually be invented. On the other hand, this study is focused on the philosophical thinking abilities of scientists who invented new great theories. They mostly had some experiences to study philosophy while studying their science fields, thus had critical thinking abilities on their studies. From my point of view, critical thinking in philosophy raised questions as to their fundamental and basic (old) concepts and principles, and thus gave them new creative theories. I will try to explain this from the point of neurophilosophy. From the perspectives coming from "the state space theory of representation" of Paul & Patricia Churchland, the pioneers of neurophilosphy, the "creative theories" are the networks of topographic maps giving new comprehensive explanations and predictions. From these perspectives, I presuppose that the attitude of critical questioning revises the old networks of maps with back-propagation or feedback, and thus, is the generative power of searching new networks of maps. From the presupposition, I can say, it is important that scientists reflect on the basic premises in their academic branches for issuing out extraordinary creativity. The critical attitude of philosophy can make scientists construct the maps of new conceptual scheme by shaking the maps of the old basic premises. From this context, I am able to propose "Critical Thinking Approach of Creativity (CTAC)".

A Study on the Direction of Private Investigation System - Focus on the bill proposal in 2012·2013 (민간조사제도의 도입 방향에 관한 연구 - 제19대 국회 발의 법안을 중심으로(2012년·2013년))

  • Cho, Min-Sang;Oh, Youn-Sung
    • Korean Security Journal
    • /
    • no.36
    • /
    • pp.525-559
    • /
    • 2013
  • Modern society has been exposed to various dangers and crimes in the process of globalization, informationization, decentralization etc. along with the development of material civilization under rapid changing societal environment. These factors are exerting a lot of effects in public security environments, as result there are gradual interest about crime and crime prevention. Realization of responsibility who take charge of social safety, from public security to private security, appears important topic at the moment. The positive point of view which private security industry is responsible to cope with security spheres instead of public security has been emerged from the reason that the public security has limitation to solve security problems for themselves. It is the time to make effort to compromise the public security and the private security industry to forecast social change and prevent dangers in the advance. In Korea, there has been close cooperation between public security and private security for decades. Strongly emerging and interesting sphere is "Private Investigation(Private Detective)" in Korea at present. There has been some proposed legislations of private investigation for decreasing burden of public security and social sympathy about possibility of private investigation system is increasing now. In this study, we focused on the introduction of private investigation system through the analysis of bill proposals for last 14 years, for instance historical aspects, contents, the differences among bill proposals. Among these, a comparison on bill proposals of the 19th National Assembly's during 2012 - 2013 were analysed mainly. We examined the importance point at issue items for introduction of private investigation system. Suggestions for introduction of private investigation system is as follows. The necessity of independent bill for developmental private investigation system is needed and the main body should be a juristic person instead of a individual for the public interest and responsibility. For the good service of private investigation and to prevent the unqualified person become a private investigator, the recruiting system and examination of private investigator should be prepared well and take into consideration anticipated problems. Also the necessity of definite jurisdiction department's appointment to divide responsibility in operation.

  • PDF

NIRS AS AN ESSENTIAL TOOL IN FOOD SAFETY PROGRAMS: FEED INGREDIENTS PREDICTION H COMMERCIAL COMPOUND FEEDING STUFFS

  • Varo, Ana-Garrido;MariaDoloresPerezMarin;Cabrera, Augusto-Gomez;JoseEmilioGuerrero Ginel;FelixdePaz;NatividadDelgado
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
    • /
    • 2001.06a
    • /
    • pp.1153-1153
    • /
    • 2001
  • Directive 79/373/EEC on the marketing of compound feeding stuffs, provided far a flexible declaration arrangement confined to the indication of the feed materials without stating their quantity and the possibility was retained to declare categories of feed materials instead of declaring the feed materials themselves. However, the BSE (Bovine Spongiform Encephalopathy) and the dioxin crisis have demonstrated the inadequacy of the current provisions and the need of detailed qualitative and quantitative information. On 10 January 2000 the Commission submitted to the Council a proposal for a Directive related to the marketing of compound feeding stuffs and the Council adopted a Common Position (EC N$^{\circ}$/2001) published at the Official Journal of the European Communities of 2. 2. 2001. According to the EC (EC N$^{\circ}$ 6/2001) the feeds material contained in compound feeding stufs intended for animals other than pets must be declared according to their percentage by weight, by descending order of weight and within the following brackets (I :< 30%; II :> 15 to 30%; III :> 5 to 15%; IV : 2% to 5%; V: < 2%). For practical reasons, it shall be allowed that the declarations of feed materials included in the compound feeding stuffs are provided on an ad hoc label or accompanying document. However, documents alone will not be sufficient to restore public confidence on the animal feed industry. The objective of the present work is to obtain calibration equations fur the instanteneous and simultaneous prediction of the chemical composition and the percentage of ingredients of unground compound feeding stuffs. A total of 287 samples of unground compound feeds marketed in Spain were scanned in a FOSS-NIR Systems 6500 monochromator using a rectangular cup with a quartz window (16 $\times$ 3.5 cm). Calibration equations were obtained for the prediction of moisture ($R^2$= 0.84, SECV = 0.54), crude protein ($R^2$= 0.96, SECV = 0.75), fat ($R^2$= 0.86, SECV = 0.54), crude fiber ($R^2$= 0.97, SECV = 0.63) and ashes ($R^2$= 0.86, SECV = 0.83). The sane set of spectroscopic data was used to predict the ingredient composition of the compound feeds. The preliminary results show that NIRS has an excellent ability ($r^2$$\geq$ 0, 9; RPD $\geq$ 3) for the prediction of the percentage of inclusion of alfalfa, sunflower meal, gluten meal, sugar beet pulp, palm meal, poultry meal, total meat meal (meat and bone meal and poultry meal) and whey. Other equations with a good predictive performance ($R^2$$\geq$0, 7; 2$\leq$RPD$\leq$3) were the obtained for the prediction of soya bean meal, corn, molasses, animal fat and lupin meal. The equations obtained for the prediction of other constituents (barley, bran, rice, manioc, meat and bone meal, fish meal, calcium carbonate, ammonium clorure and salt have an accuracy enough to fulfill the requirements layed down by the Common Position (EC Nº 6/2001). NIRS technology should be considered as an essential tool in food Safety Programs.

  • PDF

Direction and Practical Proposal for Christian Education through Ecological Christian Spirituality (생태학적 기독교 영성을 통한 기독교교육의 방향과 실천적 제언)

  • Kim, Eun-Ju
    • Journal of Christian Education in Korea
    • /
    • v.63
    • /
    • pp.347-376
    • /
    • 2020
  • This study suggests the direction and practice of Christian education through ecological Christian spirituality required in front of the ecological crisis. Environmental destruction and ecosystem problems are recognized as a serious crisis that can threaten human survival. As a result, the development of material civilization, which humanity has taken for granted, has been questioned, and changes in human consciousness and thoughts at the root of the ecological crisis have become inevitable. The crisis of civilization demands a new spirituality, and the spirituality required in front of the ecological crisis must be a life-friendly spirituality. The discourses on the ecological crisis that have emerged since the 1970s provide a fundamental perspective on the ecological crisis. Ecological spirituality such as 'immanence', 'interrelationship', 'community', 'healing and emancipation', and 'sustainability' are concepts that can understand and aggregate the discussions of the various discourses above. Based on this, this paper examines Christian ecological spirituality by dividing it into the areas of God, humans, and body. Through this, the Christian education was proposed as a practical place for self-depreciation for a simple life through the understanding of God, who emptied himself out of the transcendent God who reigns over all things, shared the pain of all things, maintained all things together, and lived in them. There, meditation and hospitality can be a place of practical Christian education where one can enrich one's inner self for a simple life. Christian education was proposed as a place of holistic knowledge through ecological Christian spirituality that emphasizes the spirituality of the body from dichotomous thinking that belittles the body. There, the Holy Communion is important as a place where both holistic education to restore the spirituality of the body and ecological education can be held at the same time. Through this, I hope that Christian education will be a place of education not only for the reason but also for the holistic knowledge of Christ and for learning how to 'together' with the ecosystem and neighbors.

Ecological Characteristics and Management Proposal of Abeliophyllum distichum Subpopulations in the Byeonsanbando National Park (변산반도국립공원 내 미선나무 아개체군의 생태적 특성과 관리제언)

  • Lim, Dong-Ok;Hwang, In-Chon;Choi, Hyon-Woo;Kim, Yong-Shik
    • Korean Journal of Environment and Ecology
    • /
    • v.23 no.2
    • /
    • pp.116-126
    • /
    • 2009
  • This study was carried out focused an ecological characteristics and habitat management of Abeliophyllum distichum subpopulations in the Byeonsanbando National Park, Korea. Among three subpopulations of the target species in the studied area, Gamaso region are known as translocation site due to the dam construction while the wild populations which is located at both the lower terrain of the Buandaem bank and Chongnim-ni, which is designated as Natural Monument No 370, is threat due to an intensive site management likes clearance of scrub amongst the Abeliophyllum plants. Vascular plant taxa in the studied sites were summarized as 182 taxa; 65 families, 143 genera, 164 species, 17 varieties and 1 form, and Gamaso area, the lower terrain of the Buandaem and Cheongnim-ni areas are summarized as 75, 102 and 89 taxa, respectively. The plant species likes persimmon tree, paulownia tree and wild mulberry tree are dominant species in the Gamaso subpopulation, while Quercus variabilis is dominant at the lower terrain of the Buandaem. The intensive site management was applied to the Cheongnim-ni subpopulation, one of the original wild habitats of the species. The population dymanics was varied; the one or two sprouting number of stems was over 87% both at Gamaso area and the lower terrain of the Buandam, while the Cheongnim-ni subpopulation recorded as 74.8%. Also three sprouting number recorded as 16% and as 9.2% for sprouting on numbers of four to eleven. The invaded species likes Chenopodium album, Rumex obtusifolius, Phytolacca americana, Pharbitis nil, Solanum lyratum, Erigeron canadensis and Erigeron annuus, were found at the wild habitat of the species, and those invaded species grow faster than Abeliophyllum plants. Among three habitats of the target species in the studied area, the habitat which in located at the lower terrain of the Buandam and Gamaso region are known as translocated due to the dam construction, and wild subpopulation at Chongnim-ni, which is designated as Natural Monument No 370, is under threatened due to an intensive site management likes clearance of scrub amongst the Abeliophyllumplants. It is one of the evidence that Cuscuta japonica at the population indicated an intensive site management likes clearance of scrub is not proper habitat management protocol. Thus, further researches should be followed to determine the effect of canopy removal and other disturbance factors as management techniques.