• Title/Summary/Keyword: Degree of Freedom

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Papers : Three - dimensional assumed strain solid element for piezoelectric actuator/sensor analysis (3 차원 가정변형률 솔리드 요소를 이용한 압전 작동기/감지기 해석)

  • Jo, Byeong-Chan;Lee, Sang-Gi;Park, Hun-Cheol;Yun, Gwang-Jun;Gu, Nam-Seo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.2
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    • pp.67-74
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    • 2002
  • The paper deals with a fully assumed strain soild element that can be used for modeling of thin sensors and actuators. To solve fully coupled field problems, the eledtric potential is regarded as a nodal degree of freedom in addition to three translations in an eighteen node assumed strain soild element. Therefore, the induced electric potential can be calculated for a prescribed load and the actuation displacement can be computed for an input voltage. Since the assumed strain solid element can alleviate locking. A finite element code is developed based on the formulation and typical numerical examples are solved for code validation. Using the code, we have conducted parametric study for THUNDER actuator. It is found that a particular combination of materials for layer curvature of THUNDER improves the actuation displacement.

로켓 모션테이블 실시간 모의시험

  • Sun, Byung-Chan;Park, Yong-Kyu;Choi, Hyung-Don;Cho, Gwang-Rae
    • Aerospace Engineering and Technology
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    • v.3 no.1
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    • pp.170-178
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    • 2004
  • This paper deals with six degree-of-freedom HILS(hardware-in-the-loop-simulation) of KSR-III rocket using a TAFMS(three axis flight motion simulator). This TAFMS HILS test is accomplished before main HILS tests in order to verify the control stability in the presence of TAFMS dynamic effects. The TAFMS HILS test includes initial attitude holding tests for INS initial alignment procedures, timer synchronization tests with an auxiliary lift-off signal, real-time calibration tests using an external thermal recorder, open-loop TAFMS operating tests, and final closed-loop TAFMS HILS tests using the TAFMS attitude measurements as inputs to the closed control loop. The HILS tests are accomplished for several flight conditions composed with nominal flight condition, TWD effect added condition, slosh modes and/or bending modes existing condition, and windy condition, etc.

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A preliminary study for the evaluation of the effects of sex education program on college students (대학생의 성교육 효과측정을 위한 기초 연구)

  • Chang, Soon-Bok;Choi, Yun-Soon;Kang, Hee-Sun;Park, So-Mi
    • The Korean Nurse
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    • v.36 no.2
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    • pp.49-63
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    • 1997
  • This study was performed to provide preliminary data for the development of a useful instrument to measure the effect of sex education. The study was conducted with the voluntary participation of 155 college students enrolled in the course "Sexuality and Relationship" at Y university in Seoul. At the end of that course, they were asked to write freely about the change they had experienced on sexuality. All meaningful statements were elicited and classified into 7 categories; "Change of Knowledge", "Enlightenment", "Change of Attitude on Sexuality", "Buildup of Ability", "Buildup of. Identity", "Change of Emotion", "Change of Behavior:' There were significant changes in the areas of knowledge(28. 6%), enlightenment(27.4%), and attitudes(20.3%) about sexuality among these 7 categories. The Change of Knowledge category consists of 3 areas: "concretion of knowledge", "increase of information", and "correction of misunderstanding." In the category of Enlightenment, total 12 areas are included: "sex role", "erception of lack of knowledge", "importance of family", "life plan", "parent role", "value of life", "equality", "sexual autonomy", "importance of sexuality", "freedom of sexuality", "perception of sexual problem", and "meaning of love." The Attitude Change category consists of 8 areas. These are "being natural", "being progressive", "being sensitive", "being truthful", "being expressive", "being cautious", "being responsible", and "being confident". The category of Buildup of Ability includes 4 areas: "problem solving", "sex education", "relationship", and "communication". The category of Buildup of Identity includes "sexual identity", and "value of sexuality". The Emotional Change category includes 3 areas: "positive feeling", "negative feeling", and "breaking from negative feeling on sexuality". The Behavior Change category includes "sex-related behavioral change". In conclusion, up to now most researches on sex education effect measures only changes of knowledge, attitude, and behavior. But we believe the changes in "Enlightenment", "Buildup of Ability", "Buildup of Identity", "Change of Emotion", should be included in addition to knowledge, attitude, and behavior in the development of an instrument to measure the sex education effects. And the effect of sex education should measure the degree of learning of autonomy, enlightenment, and ability of behavior and so on rather than studying the simple changes in sexuality.enment", "Buildup of Ability", "Buildup of Identity", "Change of Emotion", should be included in addition to knowledge, attitude, and behavior in the development of an instrument to measure the sex education effects. And the effect of sex education should measure the degree of learning of autonomy, enlightenment, and ability of behavior and so on rather than studying the simple changes in sexuality.ng the simple changes in sexuality.

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Evaluation on the Usefulness of 6DoF Couch in V-MAT on Patients with Long length of Target (표적의 길이가 긴 환자의 용적회전변조 방사선치료 시 6DoF Couch의 유용성 평가)

  • Choi, Young Se;Park, Hyo Kuk;Kim, Se Young;Kim, Joo Ho;Lee, Sang Kyoo;Yoon, Jong Won;Cho, Jung Heui
    • The Journal of Korean Society for Radiation Therapy
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    • v.29 no.2
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    • pp.53-64
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    • 2017
  • Purpose: To evaluate the usefulness of the $HexaPOD^{TM}$ evo RT system(6DoF couch) and the tendency of dose difference according to size of rotational direction error for volumetric rotational modulated radiotherapy(V-MAT) in patients with long target lengths. Therefore, it is suggested to recommend the need for rotational error correction. Materials and Methods: Ten patients with Esophagus cancer or Breast cancer including SCL treated with HexaPOD 6DoF(Six-Degree of Freedom) couch were included in this study. 6DoF couch was used to measure the difference in dose according to the rotation error in the directions of Rx(pitch), Ry(roll), and Rz(yaw). Each rotation error was applied. Positioning variation on x, y and z axis was verified and random variations were made by 6DoF couch with positioning variation. Modified DQA is conducted and point dose and gamma value are analyzed and compared. In addition, after applying the rotation error every $1^{\circ}$ to treatment plans of each target with a diameter of 3 cm, 5, 10, 15, and 20 cm respectively, gamma passing rate is being monitored by its aspect of change according to types and sizes of the target length and rotation error. Results: Mean error of the point dose and Gamma passing rate when the position variation was applied were $2.50{\pm}1.11%$ and $84.1{\pm}7.39%$ in the Rx direction, $2.36{\pm}1.16%$, and $81.0{\pm}8.49%$ in the Ry, $2.35{\pm}1.10%$ and $84.4{\pm}6.99%$ in the Rz direction, respectively. As a result of analysis on gamma passing rate according to types and sizes of the target length and rotation error, the gamma passing rate tended to decrease with increasing rotation error in the Rx and Rz directions except Ry direction. In particular, the lowest gamma passing rate (74.2 %) was in the case of $2.5^{\circ}$ rotation error in Rz direction of the target of 10 cm. Conclusion: The correction of the rotational error is needed for volumetric modulated radiotherapy of the treatment area with a long target length, and the use of 6DoF couch will improve the reproducibility of the patient position and the quality of the treatment.

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The Effects of Multi-identity on One's Psychological State and the Quality of Contribution in Virtual Communities: A Socio-Psychological Perspective

  • Suh, A-Young;Shin, Kyung-Shik;Lee, Ju-Min
    • Asia pacific journal of information systems
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    • v.20 no.1
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    • pp.57-79
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    • 2010
  • In a virtual community, one can possess multiple identities and pretend to be different by creating self-identity in contrast with his or her actual self. Does false identity undermine the qualitative growth of a virtual community by reducing members' accountability? Or does it stimulate their contributive behaviors by ensuring freedom of speech? It is imperative to understand the effects of multi-identity considering the distinct properties of a virtual community in which people easily change their identities at little or no cost. To answer these questions, we adopted the concept of self-discrepancy from the social psychology theory rooted in the concept of the self and developed a theoretical model to predict quality of contribution of the individual member in virtual communities. Based on the self-discrepancy theory, we first identified two different domains of the self: (1) an "actual self" that consists of attributes that the person believes he or she currently possesses in real life and (2) a "cyber self" that consists of attributes the person believes he or she possesses in a virtual community. Next, we derived an index for two different types of self-discrepancy by using the differences between the actual and the cyber identities: Personal Self-discrepancy and Social Self-discrepancy. Personal Self-discrepancy reflects the degree of discrepancy between actual and cyber identity regarding a person's intelligence, education, and expertise. Social Self-discrepancy reflects the degree of discrepancy between actual and cyber identity regarding a person's morality, sociability, and accordance with social norms. Finally, we linked them with sense of virtual community, perceived privacy rights, and quality of contribution to examine how having a multi-identity influences an individual's psychological state and contributive behaviors in a virtual community. The results of the analysis based on 266 respondents showed that Social Self-discrepancy negatively influenced both the Sense of Virtual Community and Perceived Privacy Rights, while Personal Self-discrepancy negatively influenced only Perceived Privacy Rights, thereby resulting in reduced quality of contribution in virtual communities. Based on the results of this analysis, we can explain the dysfunctions of multi-identity in virtual communities. First, people who pretend to be different by engaging in socially undesirable behaviors under their alternative identities are more likely to suffer lower levels of psychological wellbeing and thus experience lower levels of sense of virtual community than others. Second, people do not perceive a high level of privacy rights reflecting catharsis, recovery, or autonomy, even though they create different selves and engage in socially undesirable behaviors in a virtual community. Third, people who pretend to be different persons in terms of their intelligence, education, or expertise also indirectly debase the quality of contribution by decreasing perceived privacy rights. The results suggest that virtual community managers should pay more attention to the negative influences exercised by multi-identity on the quality of contribution, thereby controlling the need to create alternative identities in virtual communities. We hope that more research will be conducted on this underexplored area of multi-identity and that our theoretical framework will serve as a useful conceptual tool for all endeavors.

A Study of Stress Factors Experienced by the Hospitalized Patients (입원이 불안감(Stress)으로서 환자에게 미치는 영향에 관한 일 연구)

  • 최옥신
    • Journal of Korean Academy of Nursing
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    • v.5 no.1
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    • pp.93-111
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    • 1975
  • As the hospitalized patients will be facing new stress situation due to change of his environment from home to hospital it will be very important to understand the psychological stress experienced by hospital patients not only for helping patients in the process of recovery from illness but also fulfil1ing the objective of comprehensive nursing care by understanding the needs of the patients. There is no doubt that it would be very helpful for treatment of patients as well as for improvement of nursing care if we know more about psychological needs of patients and give them adequate support to meet these needs. The study to find out the causes and degree of stress events experienced by hospitalized patients, with the objective of instituting improvement of nursing care program based on the needs of patients, was conducted during the month of September 1974 with 60 patients randomly selected from those admitted to medical and surgical wards at Yonsei Medical Center in that period The questionnaire form included 36 questions which are considered to be stress events for hospital patients, and was devide into five areas namely, such events related to 1) disease itself, 2) hospital environment, 3) nursing care and treatment, 4) communication and human relations, and 5) family and economic problems. The results of the study were as follows: 1. It was confirmed that hospitalization considered to be a stress producing factor and most patients perceived the admission to hospital as a stress factor. 2. According to the rating scale, it was found that degree of perceived stress shows a variation according to the source of stress producing event. 3. No significant differences in the mean values were observed statistically with the perceived stress levels according to demographic and other variables of patients related to hospitalization. 4. Among the questions related to disease itself, "Admission for surgery" was perceived most frequently as a stress event (97.14%) by patients. 5. With regard to the questions related to hospital environment, "death of the patient room-mate" was the most serious stress event perceived by patients (90%) and "living with hospital regulations"was considered to be less serious stress event (23.33%). 6. As for the questions related to nursing care and treatment, "limitation of freedom" was perceived as a stress factor most frequently (70.91%) by the patients and "worry for wrong treatment" turned out to be less frequent stress event (50.0%). 7. As for the questions related to communication and human relations, "difficulty to meet doctors when wanted"appeared to be the most frequent stress event by the respondents (75.86%) , followed by "no explanation about treatment or examination"(75.0%) and "no explanation about nursing care procedures"(71.66%). 8. With regard 111 tile questions related to family and economic problems, "inadequate finances for family living due to hospitalization"and "high cost of hospitalization" were the most frequent cause of stress mentioned by the patients. (80.0%). 9. As a result of application of the stepwise regression analysis, it was found that about 89% was explained by those events associated with disease itself, hospital environment and family and economic problems. By adding those events related to "nursing care and treatment" and "communication and human relation", 100% of stress associated with hospitalization was explained.

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Democracy, leadership and political culture in Korea: With specific focus on political efficacy and trust (한국의 민주주의, 리더십과 정치문화: 정치효능감과 신뢰를 중심으로)

  • Uichol Kim
    • Korean Journal of Culture and Social Issue
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    • v.8 no.2
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    • pp.137-170
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    • 2002
  • The present paper reviews the development of democracy in the West and Korea. The first part of the paper provide a cultural framework for understanding the development of democracy in West and Korea. In the second part of the paper, an empirical study conducted in Korea will be presented. A survey questionnaire was developed to assess respondents' conception of political participation, political efficacy, trust, leadership, and social relations and it has been administered to national stratified sample in Korea (n=1,000). The results indicate that Korean respondents support the basic ideas of liberal democracy, such as the right to vote, participate in political organization, freedom of speech, and criticize government. At the same time, Korean respondents supported collective values, such as harmonious family life, harmonious social relations, and governmental welfare programs. Although Koreans trusted close ingroup members, such as family members and friends, they were less likely to trust their colleagues and outgroup members and were not likely to trust political and governmental institutions. Moreover, Korean respondents showed a low degree of political participation and efficacy and a high degree of political alienation. As for leadership, Koreans preferred moral and strong leaders. The overall results indicate that in Korea, although the basic ideals of democracy are valued, the method of implementing these ideals is different from the West. Detailed analysis of the results and implications of the study will be presented.

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Evaluation of the Usefulness of Exactrac in Image-guided Radiation Therapy for Head and Neck Cancer (두경부암의 영상유도방사선치료에서 ExacTrac의 유용성 평가)

  • Baek, Min Gyu;Kim, Min Woo;Ha, Se Min;Chae, Jong Pyo;Jo, Guang Sub;Lee, Sang Bong
    • The Journal of Korean Society for Radiation Therapy
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    • v.32
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    • pp.7-15
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    • 2020
  • Purpose: In modern radiotherapy technology, several methods of image guided radiation therapy (IGRT) are used to deliver accurate doses to tumor target locations and normal organs, including CBCT (Cone Beam Computed Tomography) and other devices, ExacTrac System, other than CBCT equipped with linear accelerators. In previous studies comparing the two systems, positional errors were analysed rearwards using Offline-view or evaluated only with a Yaw rotation with the X, Y, and Z axes. In this study, when using CBCT and ExacTrac to perform 6 Degree of the Freedom(DoF) Online IGRT in a treatment center with two equipment, the difference between the set-up calibration values seen in each system, the time taken for patient set-up, and the radiation usefulness of the imaging device is evaluated. Materials and Methods: In order to evaluate the difference between mobile calibrations and exposure radiation dose, the glass dosimetry and Rando Phantom were used for 11 cancer patients with head circumference from March to October 2017 in order to assess the difference between mobile calibrations and the time taken from Set-up to shortly before IGRT. CBCT and ExacTrac System were used for IGRT of all patients. An average of 10 CBCT and ExacTrac images were obtained per patient during the total treatment period, and the difference in 6D Online Automation values between the two systems was calculated within the ROI setting. In this case, the area of interest designation in the image obtained from CBCT was fixed to the same anatomical structure as the image obtained through ExacTrac. The difference in positional values for the six axes (SI, AP, LR; Rotation group: Pitch, Roll, Rtn) between the two systems, the total time taken from patient set-up to just before IGRT, and exposure dose were measured and compared respectively with the RandoPhantom. Results: the set-up error in the phantom and patient was less than 1mm in the translation group and less than 1.5° in the rotation group, and the RMS values of all axes except the Rtn value were less than 1mm and 1°. The time taken to correct the set-up error in each system was an average of 256±47.6sec for IGRT using CBCT and 84±3.5sec for ExacTrac, respectively. Radiation exposure dose by IGRT per treatment was measured at 37 times higher than ExacTrac in CBCT and ExacTrac at 2.468mGy and 0.066mGy at Oral Mucosa among the 7 measurement locations in the head and neck area. Conclusion: Through 6D online automatic positioning between the CBCT and ExacTrac systems, the set-up error was found to be less than 1mm, 1.02°, including the patient's movement (random error), as well as the systematic error of the two systems. This error range is considered to be reasonable when considering that the PTV Margin is 3mm during the head and neck IMRT treatment in the present study. However, considering the changes in target and risk organs due to changes in patient weight during the treatment period, it is considered to be appropriately used in combination with CBCT.

The Implementation and limits of Involuntary Detention of the Tuberculosis Prevention Act (결핵예방법의 격리명령의 실행과 한계에 관하여)

  • Kim, Jang Han
    • The Korean Society of Law and Medicine
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    • v.16 no.2
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    • pp.55-84
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    • 2015
  • The tuberculosis is the infectious disease. Generally, the active tuberculosis patient can infect the 10 persons for one year within the daily activities like casual conversation and singing together. The infectivity of tuberculosis can continue for a life time, and infected persons can remain at risk for developing active tuberculosis. To control this contagious disease, along with the active tuberculosis patients, non-infectious but non-compliant patients who can be infectious if their immune systems become impaired have to be managed. To control the non-complaint patients, medical treatment order should be combined with the public order. Because tuberculosis is the risk of community health, the human rights like liberty and freedom of movement can be restricted for public welfare under the article 37(2) of constitution. Even when such restriction is imposed, no essential aspect of the freedom or right shall be violated. The degree of restriction on the rights of citizens is different what methods are chosen to non-complaint patients. For example, under the directly observed therapy program, the patients and medical staffs make an appointment and meet to confirm the drug intakes according to the schedule, which is the medical treatment combined with the mildest public order. If the patients break the appointments or have the history of disobedient, the involuntary detention can obtain the legitimate cause. The Tuberculosis Prevention Act has the two step programs on this involuntary detention, The admission order (Article 15) is issued when the patients are infectious. The quarantine order (Artle 15-2) is issued when the patients are infectious and non-complaint. The legal criteria for involuntary detention are discussed and published through the international conventions and covenants. For example, World Health Organization had made guidance on human rights and involuntary detention for tuberculosis control. The restrictions should be carried out in accordance with the our law and in the legitimate objective of public interest. And the restriction should be based on scientific evidence and not imposed in an unreasonable or discriminatory manner. We define and adopt these international criteria under our constitution and legal system. Least restrictive alternative principle, proportionality principle and the individual evaluation methods are explained through the reviews of United States court decisions. Habeas Corpus Act is reviewed and adopted as the procedural due process to protect the patient rights as a citizen. Along with that, what conditions and facilities which are needed to performed quarantine order are discussed.

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Evaluation of the usefulness of IGRT(Image Guided Radiation Therapy) for markerless patients using SGPS(Surface-Guided Patient Setup) (표면유도환자셋업(Surface-Guided Patient Setup, SGPS)을 활용한 Markerless환자의 영상유도방사선치료(Image Guided Radiation Therapy, IGRT)시 유용성 평가)

  • Lee, Kyeong-jae;Lee, Eung-man;Lee, Jeong-su;Kim, Da-yeon;Ko, Hyeon-jun;Choi, Shin-cheol
    • The Journal of Korean Society for Radiation Therapy
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    • v.33
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    • pp.109-116
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    • 2021
  • Purpose: The purpose of this study is to evaluate the usefulness of Surface-Guided Patient Setup by comparing the patient positioning accuracy when image-guided radiation therapy was used for Markerless patients(unmarked on the skin) using Surface-Guided Patient Setup and Marker patients(marked on the skin) using Laser-Based Patient Setup. Materials And Methods: The position error during IGRT was compared between a Markerless patient initially set up with SGPS using an optical surface scanning system using three cameras and a Marker patient initially set up with LBPS that aligns the laser with the marker drawn on the patient's skin. Both SGPS and LBPS were performed on 20 prostate cancer patients and 10 Stereotactic Radiation Surgery patients, respectively, and SGPS was performed on an additional 60 breast cancer patients. All were performed IGRT using CBCT or OBI. Position error of 6 degrees of freedom was obtained using Auto-Matching System, and comparison and analysis were performed using Offline-Review in the treatment planning system. Result: The difference between the root mean square (RMS) of SGPS and LBPS in prostate cancer patients was Vrt -0.02cm, Log -0.02cm, Lat 0.01cm, Pit -0.01°, Rol -0.01°, Rtn -0.01°, SRS patients was Vrt 0.02cm, Log -0.05cm, Lat 0.00cm, Pit -0.30°, Rol -0.15°, Rtn -0.33°. there was no significant difference between the two regions. According to the IGRT standard of breast cancer patients, RMS was Vrt 0.26, Log 0.21, Lat 0.15, Pit 0.81, Rol 0.49, Rtn 0.59. Conclusion:. As a result of this study, the position error value of SGPS compared to LBPS did not show a significant difference between prostate cancer patients and SRS patients. In the case of additionally performed SGPS breast cancer patients, the position error value was not large based on IGRT. Therefore, it is considered that it will be useful to replace LBPS with SGPS, which has the great advantage of not requiring patient skin marking..